Author + information
- Received November 19, 2015
- Revision received April 18, 2016
- Accepted April 19, 2016
- Published online July 5, 2016.
- Jason N. Katz, MD, MHSa,∗ (, )
- Michael Minder, MDb,
- Benjamin Olenchock, MD, PhDc,
- Susanna Price, MD, PhDd,
- Michael Goldfarb, MDe,
- Jeffrey B. Washam, PharmDb,
- Christopher F. Barnett, MD, MPHf,g,
- L. Kristin Newby, MDb,h,g and
- Sean van Diepen, MD, MSci
- aDivisions of Cardiology and Pulmonary and Critical Care Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina
- bDivision of Cardiology, Duke University, Durham, North Carolina
- cDivision of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
- dDivisions of Cardiology and Critical Care, Royal Brompton Hospital, London, United Kingdom
- eDivision of Cardiology, McGill University, Montreal, Canada
- fDivision of Cardiology, University of California San Francisco, San Francisco, California
- gCritical Care Medicine Department, National Institutes of Health, Bethesda, Maryland
- hDuke Clinical Research Institute, Durham, North Carolina
- iDivisions of Cardiology and Critical Care, University of Alberta Hospital, Alberta, Canada
- ↵∗Reprint requests and correspondence:
Dr. Jason N. Katz, UNC Center for Heart and Vascular Care, 160 Dental Circle, CB# 7075, 6th Floor Burnett-Womack Building, Chapel Hill, North Carolina 27599-7075.
The cardiac intensive care unit (CICU) has changed considerably over time and now serves a unique patient population with a high burden of cardiovascular and noncardiovascular critical illness. Patient complexity and technological evolutions in the CICU have catalyzed the development of critical care cardiology, a fledgling discipline that combines specialization in cardiovascular diseases with knowledge and experience in critical care medicine. Numerous uncertainties and challenges threaten to stymie the growth of this field. A multidisciplinary dialogue focused on the best care design for the CICU patient is needed as we consider alternative approaches to clinical training, staffing, and investigation in this rapidly evolving arena.
“If you always do what you always did, you will always get what you always got.”
—Albert Einstein (1)
Driven largely by transformative technologies and an expanding collection of novel pharmacotherapies, outcomes of cardiovascular diseases have substantially improved over the last several decades. As a result of our ability to alter favorably the natural history of cardiac maladies once considered terminal, we now find ourselves caring for an increasingly older and more diverse population of hospitalized patients with escalating illness severity. Consequently, patients who occupy the modern cardiac intensive care unit (CICU) are at greater risk for adverse events and death than ever before (2). In 2007, a call to action alerted the cardiovascular community to the growing complexities of care within the contemporary CICU and an impending crisis in appropriate CICU staffing (3). This topic found additional focus in 2012 when a collaborative scientific statement created a roadmap for addressing the needs of cardiac patients with critical illness (4). Guided by an admittedly small evidence base, these investigators put forward recommendations for optimal training, staffing, and care delivery in the CICU. Although critical care cardiology is recognized as an emerging discipline, additional maturation of this field now faces numerous uncertainties and challenges (Central Illustration). In this paper, we highlight the historical underpinnings of this field, discuss key care processes and team dynamics essential to contemporary critical care delivery, evaluate potential training models for the CICU specialist, and emphasize the importance of research initiatives and collaborations in the modern CICU. Our purposes are to consider real and perceived barriers to future progress and to endorse continued critical examination of this developing specialty.
Historical Perspectives and the Origin of a Discipline
The coronary care unit (CCU) was established in the early 1960s, following the creation and implementation of continuous cardiac monitoring, cardiopulmonary resuscitation, and external defibrillation (5). These specialized units were founded on the principle that specially trained nurses could monitor, identify, and rapidly treat life-threatening arrhythmias following acute myocardial infarction (MI). The CCU was lauded for its ability to improve patient outcomes. In a landmark study by Killip and Kimball (6), for instance, a nearly 20% reduction in post-MI mortality rate was attributed to CCU care.
In 1967, Lown et al. (7) transformed the CCU from a place of reactive care to a setting focused on prevention of adverse events, including cardiac arrest. Although the strategy of arrhythmia suppression following MI that was proposed by these investigators was later dismissed (8), the idea that post-infarction complications could be proactively addressed had vast appeal, particularly at a time when clinicians had little more to offer their MI patients than analgesia and prolonged convalescence. Technological innovation promoted further conceptual shifts in the CCU and within the emerging field of critical care cardiology. Coronary reperfusion therapies, hemodynamic monitoring tools, echocardiography, mechanical circulatory support (MCS), implantable defibrillators, and new drug development have facilitated care for patients with increasing disease severity and greater baseline comorbidity. As the CCU evolved into a complex care environment catering to patients with a myriad of conditions, many institutions began to use the term CICU to represent this multidimensional care setting more accurately. Today’s CICU bears little resemblance to the CCU of the 1960s and instead shares many more similarities with today’s general and medical intensive care units (ICUs) (9–12) (Figure 1). Although many of these similarities in critical illness are likely to persist in the future, additional divergence may result from the increasing influence of novel MCS and transcatheter valve technologies (Figure 1).
Care Delivery in the Cardiac Intensive Care Unit
Structure and staffing
Organizational structure has long been a central theme of ICU care, and research has suggested that it is a key determinant of patient outcomes (13,14). One common approach to describing organizational structure in the intensive care setting is to classify units as open or closed. In an open ICU, any physician may admit a patient to the unit and then retain responsibility for orchestrating and implementing care. In a closed ICU, responsibility for patient management is transferred to a dedicated critical care team. In many hospitals, a critical care medicine (CCM) consultant is involved if desired, or this may be mandatory for certain patients. The term hybrid is used to describe ICUs with care models that fall somewhere between the open and closed definitions. Terminology is occasionally a point of contention because the term closed is considered by many practitioners to be at best ambiguous and at worst confrontational. To some investigators and providers, the closed unit moniker implies that the opinion of a patient’s primary provider may be devalued and that these providers could be excluded from vital care processes, including end-of-life decisions (15).
Published studies of organizational care models in critical care have consistently favored the closed ICU approach (13,14). However, many investigations comparing open versus closed units have been confounded by important differences in care delivery, including leadership structure, multidisciplinary team dynamics, practice heterogeneity, and provider expertise. Critical care experts, or intensivists, have also been credited with improving patient outcomes (16,17), and their participation in the care of critically ill patients has been strongly endorsed by influential health care organizations, such as the Leapfrog group (18).
Few data exist regarding the optimal organization of patient care and staffing in the CICU. One survey of largely academic hospitals revealed that 68% had a dedicated CICU for management of their critically ill cardiac patients. Among these CICUs, 55% were closed units and 45% were open units. Despite this finding, most surveyed physicians (87%) agreed that a closed CICU would deliver higher-quality and more consistent care. Furthermore, although <4% of responding CICU directors had previous training in CCM, 80% believed that the availability of cardiologists with this skill set represented an unmet need (19). A grading system for CICUs analogous to the trauma center system has been proposed; if adopted, this system would go a long way toward establishing a viable foundation for implementing staffing and organizational standards for today’s CICUs (4).
As CICU patients have grown sicker and more complex to manage, pressure to include critical care providers in their management has intensified (20). Many hospitals are actively recruiting CCM-trained physicians to staff their CICUs and cardiovascular surgical units. However, significant resistance to this trend also persists because of concerns surrounding care continuity, training requirements, and cost. These concerns are not without merit, given that emerging data suggest that today’s graduating general CCM trainees feel ill-equipped to manage cardiovascular diseases within the ICU setting (21). Ultimately, to address the organizational requirements of the CICU of the future, we will need validated practice models for cardiac critical care delivery, standardized recommendations for the advanced training of cardiologists in CCM, and renewed focus on collaborative critical care cardiology research.
Although the role of the intensivist in the CICU requires further examination, additional team members warrant particular mention:
1. Nurses. These providers have been integral team members since the inception of these specialized units, and they have long been relied on to provide autonomous care to unstable cardiac patients (22). In fact, with the advanced technologies and devices now commonly used in the CICU, the role and responsibilities of nurses have only increased over time. In the majority of hospitals, CICU nurses have already embraced the need for critical care training and often strive for their own advanced certification (23). Additionally, the importance of communication and collaboration between nurses and physicians cannot be understated because this is a key element of success in multidisciplinary critical care models (24,25).
2. Clinical pharmacists. The integration of pharmacists into the CICU team has been associated with improved patient-related outcomes, reduced rates of adverse drug events, and medication cost savings (26–28).
3. Respiratory therapists. Because increasing percentages of CICU patients are mechanically ventilated (2), respiratory therapists have become essential stakeholders in the delivery of cardiovascular critical care. These providers have been shown to improve adherence to weaning protocols, decrease ventilator days, and reduce ICU costs (29,30).
4. Advanced practice providers. Nurse practitioners and physician assistants have had increasing visibility within many of today’s ICUs and inpatient cardiovascular services (31,32). Advanced practice providers improve patient throughput and enhance communication and collaboration (33,34). As the technological complexity rises and demands on house staff within academic centers increases, advanced practice providers will likely become even more important members of the CICU team.
5. Nutritionists and dietitians. The prevalence of malnutrition among critically ill patients is estimated to exceed 50% (35). These data, combined with the observed lack of sensitivity of most objective parameters for accurate nutritional assessment when measured during critical illness, highlight the increased importance of considering the contributions of nutritionists and dietitians to CICU care (36).
6. Physical therapists. Historically, CICU patients have been nonambulatory for prolonged periods of time, originally for convalescence from MI and more recently as a consequence of invasive monitoring (e.g., Swan-Ganz catheters or percutaneous MCS). Emerging evidence now supports the safety and efficacy of therapist-guided ambulation to promote recovery (37), and efforts to improve patient mobility in the CICU are now considered best practice. In other ICU settings, physical therapists have been able to improve rates of early mobility, even among mechanically ventilated patients (38).
7. Speech therapists. These providers can support the swallowing and communication needs of a rehabilitating CICU patient.
8. Occupational therapists. These providers can help to encourage motor skill optimization in patients with resolving critical illness.
9. Palliative care experts. These specially trained physicians can help to facilitate discussions on goals of care and end of life, and they also provide support for the families of CICU patients. Furthermore, the inclusion of palliative care experts as mandatory members of durable MCS teams means that they will be called on with increasing frequency to provide consultation in the cardiac critical care setting (39).
10. Social workers, case managers, and geriatric cardiology specialists. Given the increasing use of outpatient health care services for an aging CICU patient population, including home health and skilled nursing facilities, these providers will have greater roles in helping to coordinate the vital transition from the inpatient to outpatient setting (2).
Protocols, care standardization, quality metrics, and fiscal responsibility
In a paper focused on care processes and structure, a working group of the Society of Critical Care Medicine strongly endorsed the use of uniform protocols and standardized order sets in the ICU (40). This strategy has been associated with reduced ICU lengths of stay, decreased ICU costs, and lower ICU mortality rates (40,41). Examples of commonly used ICU protocols relevant to CICU care include targeted temperature management procedures for cardiac arrest survivors, ventilator weaning and liberation algorithms, protocols for assessing and managing pain and sedation among invasively ventilated patients, ventilator-associated pneumonia prevention bundles, strategies to prevent central line–associated bloodstream infections and catheter-associated urinary tract infections, and unfractionated heparin adjustment and electrolyte replacement algorithms (42,43). In addition, with the increasing influence of percutaneous cardiac support technologies, greater use of complex arrhythmia ablation procedures, and emerging transcatheter valve interventions, consistent care protocols for managing these patients and the equipment they require are expected to become more common in the CICU.
The Centers for Medicare and Medicaid Services publicly reports 30-day risk-standardized mortality and readmission rates for diseases commonly treated in the CICU, including acute MI, heart failure, and pneumonia. In addition, the Centers for Medicare and Medicaid Services records preventable hospital-acquired conditions relevant to CICU care, including central line–associated bloodstream infection, catheter-associated urinary tract infection, pressure ulcers, patient falls, and surgical site infections (including those following placement of cardiac implantable devices), all of which are subject to substantial payment provision (44). Performance metrics have also been established for management of patients with ST-segment elevation MI and non–ST-segment elevation acute coronary syndrome (45). Hence, there is solid rationale for monitoring and targeting these ICU-based conditions. It stands to reason that to improve care delivery further, quality metrics for other common CICU conditions must also be identified, endorsed, and tracked.
Given the monumental costs of critical care delivery in U.S. health care, it is clear that fiscal responsibility is a concept that we must embrace and leverage as the field of critical care cardiology marches forward (46). The greatest drivers for critical care costs in a hospital are the number of ICU beds and their relative occupancy (47). Therefore, future studies of care delivery in the CICU must account for bed use practices and expenditures. In addition to patient-related outcomes, opportunities for cost improvements may come from the following: choosing cost-effective medication regimens; reducing medication and supply waste; avoiding redundant laboratory or ancillary studies; decreasing preventable CICU-acquired conditions and adverse drug events; defining appropriate admission and discharge criteria; and understanding more clearly the models of care and team dynamics that can shorten CICU lengths of stay, reduce CICU recidivism, and control expensive resource consumption. Similarly, although intensivists have led to savings in some general ICU settings, their financial impact in the CICU environment warrants exploration. Ultimately, because cost awareness has been historically poor in the ICU, continuing education will prove vital to establishing optimal components of cost-effective CICU care in the future (48).
Novel Thoughts on Training in Cardiac Critical Care
Provider expertise in the cardiac intensive care unit
Although the need for critical care expertise in the modern CICU may appear to be common sense, no data support this assertion. Intensivists, as previously mentioned, are frequently part of the CICU team, and there is a general anticipation that Leapfrog standards mandating intensivist involvement for all critically ill patients may soon influence CICU staffing decisions (18). Unfortunately, today’s CCM graduates lack the requisite cardiovascular knowledge base to manage critically ill cardiac patients autonomously (21). In response to a perceived training gap, leaders in fellowship education formally defined a critical care cardiology subspecialty training pathway as part of the most recent 2015 American College of Cardiology Core Training Statement (COCATS) (49). The COCATS-4 document described graduated tiers of training, ranging from Level I to III, reflective of a trainee’s skill set and clinical competence as it pertains to the discipline of critical care cardiology. Figure 2 illustrates the proposed tiers of CICU training, with a particular focus on potential pathways for achieving level III certification.
Merits and pitfalls of various training models for level III cardiac intensivists
In a scientific statement published by the American Heart Association in 2012 (4), 3 models of critical care training that would fulfill Level III requirements were proposed (Figure 2). The first model outlined a pathway by which a current graduate could serially apply for dual board certification in cardiovascular disease and CCM under the auspices of the Accreditation Council for Graduate Medical Education and the American Board of Internal Medicine (50). Although this pathway has historically functioned to train intensivists from various internal medicine subspecialty backgrounds, several potential limitations of this “one-size-fits-all” model must be considered. First, cardiovascular disease and CCM fellowship programs exist as distinct entities with separate faculty leadership, programmatic funding sources, and clinical staffing demands. Furthermore, there are currently only a few accredited, stand-alone 1-year CCM programs. As a consequence, this pathway may require a trainee to relocate to another institution within the course of fellowship training, thereby fragmenting the trainee’s education and limiting advanced training to fellows who are freely mobile.
The second training pathway proposed by the American Heart Association working group outlined a tailored curriculum in critical care cardiology. This pathway fulfills the clinical requirements for dual board certification, emphasizing key experiences in cardiac surgical intensive care, advanced heart failure, pulmonary hypertension, complex congenital heart disease, and the use of temporary and durable MCS devices (4). Institutional collaboration between CCM and cardiovascular disease leadership would be essential to create the necessary training infrastructure and funding for this type of critical care cardiology pathway, and it would currently be feasible at only a few institutions. The American Board of Internal Medicine and the Accreditation Council for Graduate Medical Education Residency Review Committee in Internal Medicine have a provision that permits accredited pulmonary and CCM programs to train 1 cardiology fellow exclusively in CCM, but not more often than once every 2 years (50). This provision may prove useful at some sites with a small number of appropriate trainees; however, for programs seeking to train cardiac intensivists on a regular basis, this would be insufficient.
A final model proposed by the American Heart Association working group would seek to create a unified 4-year training program for cardiovascular critical care specialists similar to the existing 3-year pathways currently used in pulmonary and CCM fellowships (4). This dedicated track would obviate many of the potential limitations of the previously outlined dual certification tracks and would help to streamline the trainee application and matching process, simplify funding allocation, and facilitate institutional collaborations among stakeholders. This approach would likely require uniform programmatic structures and incorporate faculty members from both cardiology and CCM. The maturing accreditation and certification process seen with the subspecialty of advanced heart failure and transplantation could provide a functional blueprint for designing and implementing this type of unified training pathway.
Acute cardiac care: Insights from the european experience
The Acute Cardiac Care Association (ACCA) of the European Society of Cardiology successfully implemented a standardized model for critical care cardiology training. In 2014, the ACCA published a core curriculum that defined optimal training standards for critical care cardiologists within member European Society of Cardiology nations (51). Similar to the COCATS-4 requirements, trainees are expected to achieve competency in general cardiology and aspects of intensive care medicine by completing a minimum of 12 months of additional training in the CICU. The ACCA Core Curriculum also defines analogous levels of competency ranging from Level I to III. Importantly, however, these organizations recognized that not all training institutions are equally equipped with the totality of advanced cardiac care technologies or clinical expertise; therefore, they chose not to define minimal training standards (51). It stands to reason that collaboration with the ACCA and European Society of Cardiology may be helpful in drafting future training pathways in the United States and, perhaps more importantly, in helping to validate the merits of such training scientifically.
Ensuring clinical competency in the cardiac intensive care unit
During training, it would be expected that assessment of fellow competency would be on the basis of direct faculty observation, in-training examinations, procedural documentation, didactic conference participation, simulation exercises, and multidisciplinary evaluations (49). The ACCA Core Curriculum endorses a similar methodology in Europe (51). There the training uses regular faculty assessments, in addition to procedural skill documentation, simulation study, and multiple-choice examination. In the United States, trainees should additionally seek to acquire dual board certification in cardiovascular disease and CCM and to maintain such accreditation throughout their clinical careers, with the hope that credentialing may eventually be simplified by the creation of an integrated critical care cardiology track and an independent board examination in the future.
Established CICU practitioners with substantial experience in the care of critically ill cardiac patients should similarly be supported to continue the practice of critical care cardiology. To ensure up-to-date expertise, there will be a need to promote continuing medical education and credentialing opportunities outside the traditional fellowship model, at least until dedicated fellowships designed to train cardiac intensivists become considerably more pervasive. In addition, a minimum requirement for clinical activity in the field should be considered, much as procedural volume standards ensure quality in the cardiac catheterization and electrophysiology laboratories today (52,53).
Priorities for Cardiac Critical Care Investigation
Current state of research
A consistent theme throughout this discussion has been the relative lack of substantial scientific evidence governing the growth of critical care cardiology as a discipline and the CICU as an effective model for care delivery. Cardiology has a successful track record of scientific discovery and therapeutic advances in largely single-system and hemodynamically stable disease states. Although there is growing recognition of the evolving critically ill case mix in the contemporary CICU (2–4), our collective research priorities have not reflected these changing patient profiles. In an analysis of ongoing phase II to IV cardiology research studies publicly shared on an Internet-based platform (clinicaltrials.gov), nearly 90% of registered trials were not applicable to critically ill patient cohorts as a result of broad exclusion criteria (54). An equally barren landscape for cardiovascular research exists within the general ICU community. Up to 38% of patients admitted to ICUs have a primary cardiovascular diagnosis, and up to one-third of patients have a cardiovascular complication of their presenting illness (55–57). Still more patients have cardiac comorbidities that may influence their management and outcomes. Despite this situation, registered and active ICU clinical trials are instead largely focused on respiratory, infectious disease, and neurological issues. In fact, fewer than 5% of studies can be expected to provide any insight into the management of cardiac patients in the intensive care setting (58).
Collectively, these findings point to a growing disparity between research efforts and our changing patient demographics. A failure to adapt research priorities, platforms, and designs to overcome current barriers means potentially contributing to an area of therapeutic uncertainty for patients at the highest risk for in-hospital morbidity and death.
Challenges to research efforts in critical care cardiology
Recognition of existing barriers to cardiovascular critical care research will be an important first step toward creating a propitious research infrastructure. We believe that, at its very foundation, this area lacks a sufficient number of academic physicians with an interest in the field, a comprehensive pathophysiological understanding of the patients intersecting the ICU and CICU, and the research training and experience required to lead these efforts. As previously noted, although it is common for clinicians in surgery, anesthesiology, and many medical subspecialties to pursue critical care certification, relatively few cardiologists today have been credentialed in both cardiology and critical care. Perhaps more importantly, few cardiologists have the research savvy or skills needed to create a prolific CICU research program. To address these barriers, it will be necessary to empower research mentorship and training programs to nurture a future generation of clinicians with the expertise necessary to pursue investigation within this maturing discipline. It will also be important to develop an infrastructure conducive to critical care cardiology research by creating joint ICU and CICU electronic health registries, by expanding and enriching current cardiology clinical trials to include subsets of patients with critical illness or noncardiac organ dysfunction, and by formalizing collaborative research networks across ICU platforms with an obligation to address the unmet research needs of this field.
It is also worth acknowledging the historically poor success rate of industry-sponsored trials in the critical care setting. In part, these failures reflect uncontrolled heterogeneity across study participants (59). Additionally, many of these earlier efforts, in retrospect, failed to identify modifiable therapeutic targets. As an example, many critically ill patients share a final common pathophysiological pathway of end-organ dysfunction. It should surprise no one then that if we categorize critical illness by these terminal syndromes (e.g., acute lung injury, cardiogenic shock, sepsis) and then attempt to target these broad entities with a single intervention, our trials will be destined to fail. Furthermore, recurrent failure may ultimately discourage sponsors from supporting risky critical care investigations. Add to that the diminishing availability of governmental funding, and there may already be a financial crisis undermining CICU collaborative investigation before it even begins. Moving forward, we will need to focus future cardiac critical care research efforts on interventions in less ambiguous disorders (e.g., type II MI in septic shock). We may also need to identify less traditional funding streams and use novel investigative approaches that can reduce research costs.
Priority topics for study
Despite the challenges inherent in critical care research, the results of several randomized trials have helped to inform clinicians and improve the care and survival of critically ill patients with primary cardiac diagnoses. Results of the SHOCK (Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock) trial (60), temperature management for patients with out-of-hospital cardiac arrest (61), and left ventricular assist device implantation for those patients with end-stage heart failure are just a few important examples (62). Nonetheless, significant care process and therapeutic knowledge gaps remain (Table 1). Identifying how best to deliver high-quality CICU care will be an important avenue for research in high-acuity cardiovascular disease populations. Given that ICU-based research has shown that closed models of care with dedicated intensivist leadership, higher institutional patient volumes, and regional systems of care for selected priority conditions (e.g., trauma, ST-segment elevation MI) are all associated with improved outcomes, it stands to reason that the implementation of regionalized care with tertiary center closed CICUs and high-intensity unit staffing models may have the potential to improve survival in lethal conditions (e.g., cardiogenic shock and cardiac arrest) (13,14,63–66). However, until this approach is proactively and prospectively studied, there will be no evidence to support this contention.
Reducing mortality rates and improving patient safety are foundational tenets of ICU care, and multiple processes unique to the ICU environment have been validated with these goals in mind. Care bundles reliably reduce nosocomial infections, and protocol-driven sedation, ventilation, and mobility pathways are associated with reductions in patient morbidity (67–70). Although universally adopted as standard of care in general ICUs, prospective investigation is needed to show a similar benefit in the CICU, given the unique mix of acute cardiovascular illnesses and comorbidities. Additionally, ICU readmission, which has been associated with increased morbidity and health care costs, is often used as a quality metric in critical care settings; however, this has yet to be substantiated among cardiac critical care cohorts (71). Although efforts are ongoing in the intensive care community to improve care transitions from the ICU to lower-acuity wards, studies addressing standardized CICU discharge criteria and optimal practices for attenuating CICU recidivism are lacking (72).
Only a few direct interventions have been shown to reduce mortality rates demonstrably for some of the highest-risk conditions treated in the contemporary CICU. The likely reason is that the care of these patients extends beyond management of the inciting pathological event alone, and instead it includes a myriad of challenges that must be overcome to avoid life-threatening complications of a patient’s ensuing critical illness. As a result, we must be able to diversify our research efforts and focus on other potential therapeutic and management targets. In conditions such as the post–cardiac arrest state, there is a vital need to construct validated prognostic models, establish evidence-based physiological and hemodynamic goals, and develop new pharmacotherapies. In addition, although critical care technologies (e.g., invasive mechanical ventilation, renal replacement therapy, and temporary circulatory support devices) all have the potential to improve clinical parameters and bolster end-organ function, the optimal timing and selection of patients who may benefit from many of these devices remain poorly defined. A similar problem exists for our colleagues in noncardiac ICUs, where cardiovascular complications such as arrhythmia, ischemia, and critical care cardiomyopathy are common. The lack of rigorous evidence in the context of critical illness means that most diagnostic and treatment recommendations are handicapped by insufficient scientific rationale (73–75). At present, neither the cardiology community nor the ICU community is well positioned to tackle these knowledge gaps alone, and collaborative efforts will be required to overcome many of the barriers to successful research. Our scientific efforts should strive to mirror the needs of our clinical practice. Without timely attention, our trial and clinical practice populations will instead continue to diverge.
Controversy and Opportunity Facing Critical Care Cardiology
With an optimistic view of the future, we recognize that proposals for new training pathways or clinical specialization in critical care cardiology have been met with appropriate circumspection. Indeed, any consideration of further specialization within the general field of internal medicine must balance perceived benefits with known and unforeseen costs (76). Fractionation of patient care, exclusion of qualified providers from the CICU, increased expenses, and new certification hurdles are important considerations that must counterbalance the clear clinical need for specialized expertise in this area. The emerging field of critical care cardiology has renewed a healthy debate about the role of the specialist, our approach to critical care training, and the optimal design and staffing of the modern CICU.
Any march toward a cardiac intensivist staffing model would be a retreat from the current standard. As previously acknowledged, this maneuver may lead to the exclusion of talented cardiologists with a wealth of CICU experience but varied areas of clinical focus. A dedicated cardiac intensivist model also risks diminished care continuity, with less nuanced understanding of the patient’s disease trajectory or previously expressed health care goals and values. These important considerations will color discussions as hospitals choose the appropriate design for their own CICUs. Given the variety of acceptable care models, it also remains to be seen whether a sufficiently large job market will exist for cardiologists trained in critical care. The New and Emerging Disciplines in Internal Medicine (NEDIM-2) statement from the American Board of Internal Medicine recommended that a “Focused Practice” must include “large numbers of internists who focus their practice in that discipline” (76). Although survey data suggest general agreement among academic cardiologists that an unmet need exists for cardiologists with specialized CCM training, there were nonetheless mixed feelings about both the feasibility and the obligation for such expertise at each surveyed institution (19).
Even the term subspecialty is problematic when applied to critical care cardiology. First, consider the clinical experience and procedural competencies recommended for critical care cardiology training programs (4). Cardiovascular medicine fellows wishing to obtain this additional training are expected to rotate through general medical and surgical ICUs, neurosurgical ICUs, and cardiac surgical ICUs. This type of training program is actually the antithesis of subspecialization. In fact, the general appeal of a dedicated cardiac intensivist is the holistic approach to patient care; the subspecialist narrows his or her focus, whereas the cardiac intensivist actually broadens his or her field of view to include pertinent noncardiovascular critical care perspectives. With the complexity of care in today’s CICU comes a proliferation of organ-specific or technology-specific specialists, each with evidence-based or experience-based recommendations for improving one aspect of a patient’s condition. The ability to integrate specialists’ recommendations and treat the entire patient requires a broad knowledge of modern CCM, cardiovascular medicine, and experience with a wide range of mechanical life support technologies and procedures. A breadth of experience allows the cardiac intensivist to navigate the hidden dangers of each path forward through a largely evidence-free field. Although additional training and a focused clinical effort are helpful in achieving this broad view, describing critical care cardiology as a subspecialty would be imprecise.
This type of comprehensive care coordination would also support the potentially vital role a cardiac intensivist could serve as part of the novel response teams seen with increasing frequency in certain academic institutions today (77,78). Surgeons, interventional cardiologists, heart failure experts, perfusionists, and others are now being called on to join multidisciplinary, hospital-based shock and thromboembolism teams that aim to treat patients with these life-threatening conditions rapidly and on an emergency basis. It is reasonable to assume that the CICU cardiologist will need to assimilate all the crucial patient data quickly, provide a conduit for communication and collaboration among the many team members, and be expected to help treat the ensuing critical illness and manage organ injury following intervention.
Ultimately, the clinical need for and the success of a disease-specific ICU are inextricably linked to the diseases treated there. The CICU was successful at its inception because acute MI required specialized nurses who were trained to use a proven therapy (i.e., defibrillation) quickly. The increasing severity and changing nature of critical illness in today’s CICU have blurred the lines that historically separated the CICU from other general or disease-specific ICUs (3). The maladies that once defined the CCU are decreasing in relevance as other critical care elements increasingly define a contemporary patient’s course in the CICU. For instance, many hospitals now admit patients with uncomplicated ST-segment elevation MI or transcatheter aortic valve replacement directly to intermediate-care units rather than to the CICU. The optimal disposition of patients with cardiogenic shock is also dynamic because the role of the percutaneous intra-aortic balloon pump has contracted, and the use of more robust, surgically placed, temporary MCS devices is increasing. Furthermore, as the lines separating ICUs blur, the importance of cardiac and vascular disease among patients with primary noncardiovascular critical illness appears to be expanding. The incidence of advanced heart disease is growing, and these patients are predisposed to critical illness, whether cardiovascular or noncardiovascular. Additionally, the increasing role of venovenous extracorporeal membrane oxygenation in the management of advanced respiratory failure has enhanced the value of expertise in vascular access and assessment of right-sided heart function in the medical ICU. Thus, the consideration of critical care cardiology as a clinical focus comes with a re-examination of the “silo” model of ICU care more generally. Undoubtedly, opinions will be mixed regarding the optimal evolution for the CICU of tomorrow and for ICUs in general. Disagreement is healthy and is necessary to facilitate thoughtful dialogue.
The field of critical care cardiology has undoubtedly grown over the past several years, and many members of the cardiovascular community now recognize its potential merit. However, only through thoughtful dialogue and multidisciplinary collaboration can we hope to navigate the many barriers that still threaten broad acceptance of this field. We must acknowledge that there is still much to learn about how best to care for critically ill patients with cardiac disease, how to identify providers who may be best suited to coordinate care for these complex patients, and how best to equip future providers with the necessary skills for doing so. Much of what we ultimately learn will come from synergistic and well-orchestrated research endeavors specific to the contemporary patients we now see in the cardiac intensive care setting. If we continue to do what we have always done for our critically ill cardiac patients, we have little hope of improving care delivery or outcomes for this evolving and increasingly complex population. Future prosperity of this maturing discipline hinges on innovations and novel perspectives that will challenge the status quo.
Dr. van Diepen has received grant support from the Heart and Stroke Foundation and the University Hospital Foundation. Dr. Newby is a consultant for BioKier, Metanomics, Merck, Roche Diagnostics, and Philips Healthcare; is a researcher for Metanomics, Sanofi, GlaxoSmithKline, and Verily (formerly Google Life Sciences); is on the data and safety monitoring board of DemeRx; is on the advisory board of MedScape/theHeart.org; has received research funding from the National Institutes of Health and the Patient-Centered Outcomes Research Institute; and has received honoraria from JACC: Basic to Translational Science and the Journal of the American Heart Association. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- Acute Cardiac Care Association
- critical care medicine
- coronary care unit
- cardiac intensive care unit
- intensive care unit
- mechanical circulatory support
- myocardial infarction
- Received November 19, 2015.
- Revision received April 18, 2016.
- Accepted April 19, 2016.
- American College of Cardiology Foundation
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