Author + information
- Shilpa Sharma, MD,
- Guy Rozen, MD, MHA,
- Jessica Duran, MD,
- Theofanie Mela, MD and
- Malissa J. Wood, MD∗ ()
- ↵∗Department of Cardiology, Echocardiography, Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114-2696
The incidence of spontaneous coronary artery dissection (SCAD), defined as nontraumatic, noniatrogenic, and nonatherosclerotic separation of the coronary artery wall, is rising with increasing awareness and advances in diagnostics. Optimal management of SCAD patients remains unclear because recommendations are primarily based on observational series. Furthermore, there are no published reports on implantable cardioverter-defibrillator (ICD) therapy for SCAD patients. ICD therapy is sometimes used in SCAD patients especially after sudden cardiac death (SCD) but the benefits are unclear and placement has risks. We initiated the Massachusetts General Hospital (MGH) SCAD registry to gather contemporary data regarding the clinical characteristics and management of these patients. We aimed at assessing the risks of SCD and use of ICD therapy in SCAD.
Currently, the MGH SCAD registry includes 102 patients, all presenting to MGH with SCAD or referred after a SCAD episode. Fourteen patients experienced SCD, and 7 underwent ICD placement. The SCD rate observed in our registry is higher than reported (1) because patients with SCD are more likely to be referred to a specialized SCAD center such as MGH for further management. Of the SCDs, 7 (50%) occurred out of hospital, 4 (29%) in the emergency department, and 3 (21%) during or shortly after percutaneous coronary intervention (PCI). Table 1 summarizes clinical characteristics of SCAD patients who experienced SCD (n = 14) versus those who did not (n = 88). Patients with SCD were more likely to be peripartum, tobacco users, present with ST-segment elevation myocardial infarction, receive an ICD, and had higher incidence of repeat SCAD.
As for ICD placement, 5 of 7 were for secondary prevention. Timing of placement ranged from initial presentation (n = 3) to 1 month post-discharge with a life vest based on patient preference (n = 1) to several months post-discharge after detection of inducible ventricular tachycardia (VT) (n = 1). Of 7 ICD placements, 2 were for primary prevention, 1 for inducible VT, and the other 4 for recurrent episodes of nonsustained VT. During a mean follow-up of 3.5 years, 1 patient received an ICD discharge for supraventricular tachycardia, and 1 patient had significant ICD complications. Four additional individuals received life vests, most commonly in setting of low ejection fraction. All 4 patients had normal ejection fractions within 2 months, resulting in discontinuation.
The SCD cases in our registry emphasize the need for universal cardiopulmonary resuscitation/automated external defibrillator training because one-half occurred out-of-hospital. One-half of the SCDs cases in the emergency department occurred in the waiting room, indicating the need to raise awareness about SCAD, specifically appropriate triaging of patients presenting with chest pain regardless of age or lack of traditional cardiac risk factors. Several cases of SCD occurred during PCI, emphasizing the published reports that PCI in SCAD is associated with low success rates and high risk of iatrogenic injury (2).
SCAD complications are alarmingly prevalent with an estimated 10-year rate of major adverse cardiovascular events of 47% and SCAD recurrence rate of 29% (3). Therefore, ICD therapy in SCAD patients intuitively makes sense. However, data currently support ICD therapy only for secondary prevention in the absence of reversible causes and for primary prevention in patients with persistently low left ventricular ejection fraction. SCAD lesions usually heal spontaneously, and ejection fraction is often preserved or recovers shortly after short-term presentation (1). Furthermore, preliminary outcomes from our SCAD registry suggest that complications of ICD therapy may outweigh benefits. Finally, SCAD patients possibly could decrease their risk of SCD by avoiding future pregnancies and quitting smoking, risk factors associated with SCD in our study.
Our dataset is currently limited in size and follow-up, but raises several important issues. ICD therapy in SCAD should be addressed, given that patients with SCD are not well represented in the current SCAD published reports and that despite lack of data on ICD therapy in SCAD, it is sometimes employed in practice. Although ICD therapy may intuitively make sense, the risk–benefit ratio in SCAD is unclear. Most importantly, nationwide collaborative efforts are imperative to consolidate existing data from SCAD and SCD registries to guide ICD placement in SCAD patients.
Please note: This work was funded by the Corrigan Minehan Heart Center Spark Award, Massachusetts General Hospital, Boston, Massachusetts. Dr. Mela has received speaker honoraria from Medtronic, Biotronik, St. Jude, and Boston Scientific. Dr. Wood has been a consultant for Boehringer Ingelheim. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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