Author + information
- Bardia Arabkhani, MSc,
- Helena J. Heuvelman, MD,
- Ad J.J.C. Bogers, MD, PhD,
- M. Mostafa Mokhles, MSc,
- Jolien W. Roos-Hesselink, MD, PhD and
- Johanna J.M. Takkenberg, MD, PhD⁎ ()
- ↵⁎Department of Cardio-Thoracic Surgery, Erasmus Medical Centre, Rotterdam, 3000 CA, the Netherlands
To the Editor:
There is insufficient published evidence about the potential degenerative effects of pregnancy on the homograft and pulmonary autograft in the aortic position. To assess the association between pregnancy and accelerated degeneration of human aortic valve substitutes, we conducted a retrospective analysis of a prospective cohort study of female patients who received a human tissue valve in the aortic position at our institution.
All patients who have received a homograft or autograft in the aortic position in our center since 1987 are enrolled in an ongoing prospective follow-up study (1). Patients undergo annual clinical follow-up and biennial standardized serial echocardiography (aortic gradient [Vmax]), aortic regurgitation (AoI), and annular and sinotubular junction diameter (AD and STJ). We identified 108 female patients who underwent 59 homograft and 49 autograft procedures, and who were ≤50 years old at the time of surgery and at least 16 years old at the time of study (age 29 ± 13 years). Informed consent was obtained from the patients to interview them (December 2010) for additional information on pregnancy and cardiac status (institutional review board number 2010–272).
Freestanding root replacement with reimplantation of the coronary arteries was performed in most patients. Fifteen homograft patients underwent a subcoronary homograft implantation, and 2 autograft patients had an inclusion cylinder aortic root replacement.
Outcome was reported according to the 2008 American Association of Thoracic Surgery/European Association of Cardio-Thoracic Surgery/Society of Thoracic Surgeons guidelines for reporting mortality and morbidity after cardiac valve interventions. Mixed-effects models were used to assess changes in echocardiographic measurements over time while accounting for within-patient correlation between repeated follow-up measurements (2). Total follow-up was 1,448 patient years and 99% complete. Ninety-nine patients had ≥1 echocardiographic examinations (median 6; range 1 to 11).
Thirty-one patients (13 homografts and 18 autografts) experienced 55 pregnancies, including 48 completed pregnancies, 4 elective abortions for noncardiac reasons, and 3 miscarriages. Homograft recipients without pregnancies were older than homograft recipients who became pregnant (35 vs. 28 years; p = 0.02). There were no other differences in patient characteristics between homograft and autograft patients without pregnancies and those who became pregnant.
During follow-up, 9 homograft patients and 4 autograft patients died. Fifteen-year survival in homograft patients was 80.0 ± 7.3% for patients without pregnancies and 100% for patients with pregnancies; in autograft patients, this was 94.1 ± 4.0% for patients without pregnancies and 94.4 ± 5.4% for patients with pregnancies (p = NS).
Fifteen homograft patients required reoperation for a calcified and degenerated homograft; 2 additional homograft patients were reoperated for paravalvular leak. Twelve autograft patients were reoperated for neoaortic regurgitation and dilation of the neoaortic root, including 11 autograft replacements and 1 valve-sparing aortic root replacement (Yacoub procedure). Freedom from aortic valve reoperation at 15 years was 63% (95% confidence interval [CI]: 57% to 69%) in homograft patients; in autograft patients, this was 75% (95% CI: 63% to 87%). Freedom from reoperation was comparable between patients who experienced pregnancy and those who did not, in both homograft and autograft recipients (p = NS).
Figure 1 shows progression of Vmax, STJ diameter, AD, and AoI over time. Pregnancy was not associated with changes in Vmax over time, STJ diameter over time, AD over time, or AoI grade over time for either valve type.
Pregnancy is known to produce significant hemodynamic changes, with an increase in heart rate, plasma volume, and cardiac output (3). This may impose a burden on biological valve substitutes, accelerating degeneration. However, we found that pregnancy was not associated with either homograft or pulmonary autograft valve reoperation and echocardiographic valve function over time. This is in concordance with previous, but very limited, evidence (4,5).
The question remains as to what the best valve substitute choice is for young female patients who require aortic valve replacement, and who may contemplate pregnancy. Bioprosthetic valves are an option, but valvular deterioration seems to accelerate during pregnancy (6). Mechanical prostheses are far from ideal during pregnancy because of anticoagulation therapy-related complications, although in some patients mechanical valves are the only option. Human tissue valves do not require anticoagulation therapy and have good hemodynamic performance, but homografts—in contrast to autografts—do not increase in size with the growing child. In addition, autografts have a superior hemodynamic profile (7), which particularly during pregnancy has potential beneficial effects on cardiac function. In contrast, neoaortic root dilation and neoaortic regurgitation cause an increased need for reoperation (8).
Because human tissue valve durability is not influenced by pregnancy, it offers an attractive biological option for aortic valve replacement in young female patients. Young female patients who (may) contemplate pregnancy should consider human tissue valves as a suitable aortic valve substitute.
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