Pregnancy and congenitally bicuspid aortic valve (BAV) are thought to be risk factors for aortic dissection; however, the population-based risk for patients with the 2 risk factors remains unknown. We investigated the relation between pregnancy and ascending aortic events in women with congenital BAV living in Olmsted County, Minnesota. Our institutional echocardiographic database was searched for women residing in Olmsted County with congenital BAV diagnosed from 1980 to 1999. We reviewed medical records for end points of aortic events (dilatation, dissection, or surgery) and aortic valve replacement (AVR). Obstetric history and further outcome follow-up were collected by postal survey. We identified 88 women with BAV. Median age at diagnosis was 35 years. Obstetric history totaled 216 pregnancies and 186 deliveries. There were no aortic dissections. During follow-up (median 12.3 years), 24 patients underwent AVR (n = 14), ascending aortic surgery (n = 3), or AVR and ascending aortic surgery (n = 7). Pregnancy was not associated with dilatation of the aorta, aorta surgery, or AVR. At echocardiographic diagnosis of BAV, 5 patients (6%) had aortas >40 mm in greatest diameter and 1 patient has >50 mm. Of 60 patients with serial echocardiograms for comparison (median interval 10.7 years), 21 patients (35%) had aortas measuring >40 mm in greatest dimension and 2 patients had >50 mm. In conclusion, aortic dissection in women with BAV and pregnancy is rare in the community. There is a significant rate of progressive enlargement of the aorta, warranting longitudinal follow-up.
Bicuspid aortic valve (BAV) is associated with dilatation of the ascending aorta in 30% to 50% of patients. Clinical studies have demonstrated that presence of aortic dilatation places affected patients at 6 to 10 times greater lifetime risk of aortic dissection compared to the general population. Furthermore, it has been suggested by some that the aortopathy associated with BAV places these patients at particular risk of complications, and that aortic dissection may occur in them at smaller aortic diameters. These observations pose a particularly challenging clinical problem for the young woman with BAV who is pregnant or contemplating pregnancy. The risk of aortic dissection during pregnancy specifically for women with BAV is unknown. Aortic dissection during pregnancy has been reported; however, its anecdotal nature prohibits assessment of population-based risk. Because congenital BAV is present in 1% to 2% of the general population, the impact of estimated risk of dissection in this setting has a profound clinical and social impact. Should pregnancy be discouraged or even terminated? Should the ascending aorta be prophylactically replaced, and if so, should a mechanical valve prosthesis be employed? We therefore sought to define the association between pregnancy and aortic dissection by performing a community-based study of women of childbearing age with BAV living in Olmsted County, Minnesota, taking advantage of our position as unique regional medical care providers.
Methods
In addition to providing tertiary and quaternary referral care, the Mayo Clinic (Rochester, Minnesota) is a regional care center and is the sole provider of echocardiographic services and cardiac surgery in Olmsted County. Furthermore, our institution provides coroner services for the county. Search of the computerized echocardiographic database at our institution should therefore provide near complete ascertainment of all patients diagnosed with BAV echocardiographically and all peripartum aortic surgical procedures including acute dissections. We searched for women with congenital BAV living in Olmsted County from January 1980 to December 1999 who were ≥18 years of age. Women with Marfan syndrome or other known connective tissue disorders were excluded. Patient demographic and clinical outcome data were obtained from medical records and postal surveys were used to collect obstetric history including number of pregnancies, number of deliveries, and mode of delivery (vaginal delivery or cesarian).
Clinical follow-up was obtained by review of medical records and postal surveys. Clinical end points included aortic dissection, ascending aortic dilatation, ascending aortic surgery, and aortic valve replacement (AVR). Follow-up echocardiogram, when available (60 patients), was analyzed for progression of aortic dilatation.
All patients underwent baseline clinical evaluation performed by a physician and comprehensive 2-dimensional and Doppler echocardiographic evaluation with state-of-the-art technology at diagnosis. Diagnosis of BAV was based on short-axis imaging of the aortic valve demonstrating the existence of only 2 commissures delimiting only 2 aortic valve leaflets. Multiple views were obtained with repeat imaging to confirm the bicuspid valve, if necessary. Two-dimensional measurements of the ascending aorta were made with appropriate aortic visualization in systole at the proximal ascending aorta level.
Descriptive statistics for categorical variables are reported as frequency and percentage and continuous variables are reported as mean ± SD or median (range) as appropriate. Categorical variables were compared between patients with enlarged aortas by chi-square test and continuous variables were compared using 2-sample t test or Wilcoxon rank-sum test where appropriate. Comparisons in patients with 0 pregnancy, 1 pregnancy to 2 pregnancies, and ≥3 pregnancies were conducted using chi-square test for categorical variables and analysis of variance or Kruskal-Wallis test for continuous variables.
Results
We identified 88 women with congenital BAV residing in Olmsted County. Median age at diagnosis of BAV was 35 years (1 to 59; Table 1 ). Aortic stenosis was the most common functional valve pathology ( Table 2 ). At diagnosis of BAV, 6 patients (7%) had aortas >40 mm in greatest dimension and 1 patient had >50 mm. Obstetric history was available among 82 patients for a total of 216 pregnancies and 186 deliveries (16 patients gravida 0, 33 patients gravida 1 to 2, and 33 patients gravida ≥3). Thirteen patients had echocardiographic diagnosis of BAV before known pregnancies. Sixty patients (68%) had >1 echocardiogram available for comparison.
| Continuous Variables | Number | Mean ± SD |
|---|---|---|
| Age at diagnosis of bicuspid aortic valve (years) | 88 | 35.3 ± 20 |
| Gravidity | 2.6 ± 2.0 | |
| Parity | 2.3 ± 1.8 | |
| Surgery (years after diagnosis of bicuspid valve) | 24 | 13 ± 7 |
| Pregnancy (yes) | 67 (82%) | |
| Total gravidity | 216 | |
| Total parity | 186 | |
| Surgery | 24 (27%) | |
| Aortic valve replacement | 14 (16%) | |
| Aortic valve replacement and aortic surgery | 7 (8%) | |
| Aortic surgery | 3 (3%) |
| Variable | Mean | Median (range) |
|---|---|---|
| Age at surgery (years) | 44.6 | 43.3 (12–73) |
| Valve pathology (%) | ||
| Aortic stenosis | 12 | 14 |
| Aortic regurgitation | 1 | 1 |
| Combined stenosis and regurgitation | 2 | 2 |
| Stenosis and aneurysm | 4 | 5 |
| Regurgitation and aneurysm | 2 | 2 |
| Combined stenosis/regurgitation with aneurysm | 1 | 1 |
| Other | 4 | 5 |
| Surgery (%) | 24 | 27 |
| Isolated aortic valve replacement | 14 | 16 |
| Aortic valve repair and aortic repair | 7 | 8 |
| Isolated aortic repair | 3 | 3 |
There were no aortic dissections observed in these patients at a median follow-up of 12.3 years (0 to 26). Indeed, search of autopsy records at the Mayo Clinic to 1950 revealed only 1 peripartum acute aortic dissection occurring in a resident of Olmsted County, with that being a type B dissection in the setting of eclampsia but not BAV. Of study patients, 24 (27%) ultimately underwent surgical intervention at a median 12 years (0.02 to 26) after diagnosis of BAV. Fourteen patients (16%) had AVR, 7 patients (8%) combined AVR and ascending aortic surgery, and 3 patients (3%) isolated ascending aortic surgery ( Table 2 ). In addition, of 60 patients for whom surveillance echocardiograms were available (median follow-up 10.7 years, 1 to 19), there was documented progression of aortic dilation in 23 patients (38%) at a median rate of growth of 0.4 cm/year. Specifically, 21 patients (35%) showed aortic enlargement to >40 mm and 2 patients showed progression to >50 mm. No patients in this subset underwent surgery for isolated aortic aneurysm replacement but 2 underwent AVR for stenotic aortic valves and had concomitant ascending aortic replacement. One additional patient underwent AVR for a regurgitant valve and replacement of a 50-mm ascending aorta. There was no association between gravidity and AVR, development of aortic dilatation, or surgery of the ascending aorta ( Table 3 ). There was, however, a positive association between increasing age and number of pregnancies (p = 0.001, data not shown) and aortic dilatation or surgery.
| Para 0 (n = 16) | Para 1–2 (n = 33) | Para >3 (n = 33) | p Value | |
|---|---|---|---|---|
| Aortic valve replacement | 2 | 8 | 10 | 0.49 |
| Aortic repair | 3 | 1 | 6 | 0.22 |
| Aortic enlargement (>40 mm) | 2 | 1 | 5 | 0.43 |
| Patients with aorta >40 mm | 25% | 31% | 41% | 0.67 |
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