Pregnancy in patients with a porcine valve bioprosthesis

The Stented Porcine Bioprosthesis: A 50-Year Journey Through Hopes and Realities

The year 2018 marked the 50th anniversary of the first implant of a commercially manufactured stented porcine bioprosthesis. During the subsequent years considerable clinical and pathologic research was done to evaluate the overall performance of such devices and to identify the leading causes of failure. This brief review covers 5 decades, summarizing the initial hopes and the realities faced by surgeons who have believed from the start in these cardiac valve substitutes. From reported failures and long-term results a new generation of durable and reliable stented porcine bioprosthetic valves is currently available.

Echocardiography in Pregnancy: Part 2

The prevalence of pregnant women with cardiovascular heart disease is increasing. Transthoracic echocardiography is safe during pregnancy, and it is an important diagnostic tool in pregnant women with established heart disease in order to monitor ventricular and valvular anatomy and function. In addition, it can be used to delineate cardiac anatomy in complex congenital heart disease and help stratify maternal risk during pregnancy. This review will focus on the use of echocardiography in the diagnosis and management of pregnant women with common congenital lesions and with prosthetic valves.

Pregnancy does not accelerate biological valve degeneration

BACKGROUND

Pregnancy in women with biological heart valve prosthesis might lead to a faster degeneration of the prosthesis. We analyzed the rate of prosthesis replacement and the outcome of pregnancies in women with biological valve prosthesis.

METHODS

Between 1976 and 2006, 100 female patients aged 18-40 years at time of the study, underwent a valve replacement with a bioprosthesis or a homograft. At a mean interval of 10.8±8 years, 87 patients were evaluated by a questionnaire.

RESULTS

A biological prosthesis was implanted in 45 patients (52%), while 42 patients (48%) received a homograft. After valve replacement, 33 patients (38%) had a total of 56 pregnancies with a live-birth rate of 77% (n=43). There were 9 (16%) miscarriages, 4 (7%) therapeutic abortions and no stillbirths. There was no maternal death, thromboembolic event or structural valve deterioration during pregnancy. Out of 87 patients, 31 (36%) required a valve re-replacement at a mean time of 9.5±5 years. Neither age, valve type, valve position nor pregnancy were a risk factor for a valve re-replacement. The freedom from valve re-replacement at 5 and 10 years, was 96±3% and 73±9%, respectively for patients after a pregnancy compared to 93±4% and 52±10%, respectively for patients without a pregnancy (p=0.2).

CONCLUSIONS

Pregnancy does not accelerate the risk for replacement of a biological heart valve prosthesis. Pregnancy in women with biological heart valves can be carried out without increased morbidity related to the implanted valve.

Emergency redo mitral valve replacement in a pregnant woman at third trimester: case report and literature review

Pregnancy carries significant physiological changes that demand more cardiac output, so structural cardiac disease can cause life-threatening complications. A woman had rheumatic mitral stenosis and underwent mitral valve replacement (MVR) with bioprosthesis 8 years prior to admission. She presented with dyspnea and leg edema at 30 weeks of gestation. Severe mitral stenosis caused by xenograft failure was noted on echocardiography. Management was conservative until a sudden onset of hemodynamic compromise requiring emergency redo MVR under normothermic cardiopulmonary bypass with intra-aortic balloon pump. Monitoring of fetal heartbeat and uterine contractions showed no significant abnormalities and the woman gave birth to a full-term baby by Cesarean section with postoperative warfarin therapy.

Pregnancy in patients with heart disease: experience with 1,000 cases

BACKGROUND

Previously, the high maternal mortality in cardiac patients who became pregnant prompted the assertion: Women with an abnormal heart should not become pregnant. This long-standing notion needs to be revised today.

HYPOTHESIS

The study was undertaken to ascertain the experience with a large series of pregnant women with cardiac disease cared for in the same referral center.

METHODS

From 1989 to 1999, 1,000 pregnant women with heart disease were followed by the same clinical and obstetric team. The cardiac diseases included rheumatic heart disease (55.7%), congenital heart disease (19.1%), Chagas' disease (8.5%), cardiac arrhythmias (5.1%), cardiomyopathies (4.3%), and others (7.3%).

RESULTS

Of the pregnant women studied, 765 (76.5%) experienced no cardiovascular events during the study; 235 (23.5%) patients had the following cardiovascular complications: congestive heart failure (12.3%), cardiac arrhythmias (6%), thromboembolism (1.9%), angina (1.4%), hypoxemia (0.7%), infective endocarditis (0.5%), and other complications (0.7%). Clinical treatment allowed adequate management in 161 (68.8%) patients; however, 46 (19.6%) patients underwent interventional procedures because of refractory complications. The general maternal mortality rate was 2.7%. Of the 915 (91.5%) infants who were discharged, 119 (13%) were premature.

CONCLUSION

Pregnancy in women with heart disease is still associated with considerable morbidity and mortality rates, which strongly correlate to maternal underlying disease. Strict prenatal care and early risk stratification during gestation are fundamental measures to improve the prognosis of pregnancy in women with heart disease.

Effect of oral anticoagulant during pregnancy with prosthetic heart valve

This retrospective study aimed to evaluate the risks and outcome of oral anticoagulant use during pregnancy in women with prosthetic heart valves. Between December 1989 and November 1998, 192 females of childbearing age underwent heart valve replacement with a mechanical prosthesis. There were 37 pregnancies in 30 patients during follow-up. Pregnancy was terminated on medical grounds in 5 cases, there were 2 (6%) spontaneous abortions, and 1 (3%) premature birth of a normal baby who died 24 hours later due to asphyxia. The other 29 pregnancies (91%) went to full term and the mothers continued taking oral anticoagulants until a week before the expected date of delivery, then switched to heparin. There was no thromboembolism, valve thrombosis, or maternal mortality. Three babies (10%) had a skeletal deformity: nasal hypoplasia in all 3, with cleft pinna in 1. Continuation of oral anticoagulants during pregnancy provided adequate protection against thromboembolism and valve thrombosis, but the risks of fetal abnormalities and premature delivery should be explained to women of childbearing age with a mechanical valve prosthesis.

Pregnancy outcomes and cardiac complications in women with mechanical, bioprosthetic and homograft valves

OBJECTIVES

Firstly, to compare pregnancy outcomes and cardiac complications in women with: 1) either mechanical or bioprosthetic valves at the mitral site; 2) mechanical valves treated with warfarin or subcutaneous heparin. Secondly, to determine pregnancy and cardiac outcomes in women with aortic homograft valves.

DESIGN

Historical cohort study.

SETTING

Greenlane Hospital, Auckland, New Zealand.

POPULATION

Young women (n = 255) who had valve replacements between 1972 and 1992. Seventy-nine women underwent 147 pregnancies.

MAIN OUTCOME MEASURES

Pregnancy loss, cardiac complications.

RESULTS

Pregnancy loss occurred in 59% of pregnancies with mitral mechanical valves (n = 50) and 7% with mitral bioprosthetic valves (n = 33) (RR 8 x 20, 95% CI 2 x 10-31 x 93). Pregnancy loss rate was 70% in pregnancies treated with warfarin, compared with 25% for those switched from warfarin to heparin (RR 2 x 81, 95% CI 1 x 03-7 x 73). All heparin-associated losses occurred in the first trimester, whereas there were four stillbirths with warfarin. Cardiac complications occurred in 10 pregnancies (20%) in the women with mitral mechanical valves and four (13%) with mitral bioprosthetic valves (RR 1 x 55, 95% CI 0 x 53-4 x 52). All four thromboembolic complications with mechanical valves occurred in the 14 women treated with heparin throughout pregnancy. Structural valve deterioration occurred in four pregnancies (10%) with mitral bioprosthetic valves. No cardiac complications or known pregnancy losses occurred with aortic homograft valves (n = 41).

CONCLUSION

The high pregnancy loss rate in women with mitral mechanical valves was associated with warfarin throughout pregnancy, whereas the thromboembolic cardiac complications were associated with heparin. Pregnancy outcome was very good in women with bioprosthetic and homograft valves.

Effect of pregnancy on the duration of bovine pericardial bioprostheses

BACKGROUND

This study sought to evaluate the effect of pregnancy on the rate of deterioration of bovine pericardial bioprostheses. To avoid the fetal and maternal risks associated with anticoagulant therapy during pregnancy, the use of bioprostheses has been advocated for young women with cardiac valve disease who may later wish to bear children. Several reports have suggested the probability of pregnancy-related accelerated deterioration of these valves.

METHODS AND RESULTS

The incidence of prosthetic dysfunction and the freedom from deterioration were investigated in 48 women who had 58 pregnancies and in a control group of 167 patients in the same age range. There were 39 cases of prosthetic dysfunction (deaths plus reoperations resulting from valve failure): 12 in the pregnant group for a linearized rate of 3.5% +/- 0.99% (SE) per patient-year and 27 in the control group or 3.4% +/- 0.65% per patient-year (P = not significant). The actuarial freedom from dysfunction was 90.4% (95% confidence interval 77.9 to 96.2) at 5 years and 77.0% (59.7 to 88.3) at 8 years for the pregnancy group and 86.3% (77.3 to 92.0) and 73.4% (56.6 to 84.8), respectively, for the control group ( P = not significant). In the Cox proportional hazard regression analysis, pregnancy did not influence dysfunction. A direct correlation was found between freedom from dysfunction and the patient's age at surgery.

CONCLUSIONS

Pregnancy does not accelerate the rate of deterioration of bovine pericardial bioprostheses. It is more likely that biological valves deteriorate more rapidly in these patients because of their young age.

Pregnancy following cardiac valve replacement surgery

OBJECTIVES

To study the outcome of pregnancy in women with artificial heart valves and to compare the maternal and perinatal outcome in mechanical and bioprosthetic valves.

METHOD

Retrospective analysis of 34 pregnancies in 29 women who conceived after cardiac valve replacement was carried out.

RESULTS

The majority of women (76.4%) delivered within 5 years of valve replacement. Anticoagulants were administered in 79.4% of pregnancies. Maternal mortality was 2.9% and maternal morbidity in the form of heart failure, atrial fibrillation, valve thrombosis, thromboembolism, bleeding complications and non-functioning prostheses were 2.9%, 5.8%, 2.9%, 2.9%, 11.7% and 2.9%, respectively. The incidence of prematurity was 5.8% and small for gestational age babies was 11.7%. There was no case of abortion. Two babies (5.8%) were still born, one of which had malformations. Maternal complications were significantly higher in women with bioprostheses, though the complications were more grave in the mechanical prostheses group. The perinatal outcome was almost similar in both the groups.

CONCLUSION

The perinatal outcome was not different in women with bioprosthetic valves from the ones with mechanical prostheses, but the maternal morbidity was more in women with bioprosthetic valves. Coumarin derivatives were safe and effective and did not lead to embryopathy.

Modern management of prosthetic valve anticoagulation

Prosthetic heart valves have been effectively used for many years. Nonetheless, they are associated with risks of thrombosis and thromboembolic events, as well as anticoagulation-induced bleeding. Substantial changes in anticoagulation measurement and dosing have occurred during the past several years. In this review, the rationale for anticoagulation in patients with prosthetic heart valves, the changes in monitoring and dosing, and the comparison of relevant anticoagulation trials are discussed. On the basis of the existing data, new recommendations regarding lower anticoagulation levels are offered, utilizing a single value goal rather than the traditional therapeutic range. Perioperative management of anticoagulation is discussed in light of the available literature, and major drug interactions are reviewed.

Heparin in calcification prevention of porcine pericardial bioprostheses

Calcific degeneration is the main cause of failure of glutaraldehyde-treated xenograft heart valve substitutes implanted in humans. Coupling of heparin through an intermediate surface-bound substrate containing amino groups showed complete prevention of calcification of glutaraldehyde-treated porcine pericardium implanted subdermally in weanling rats for 5 months (heparin bonded pericardium: calcium, 0.625 +/- 0.24 mg g(-1); glutaraldehyde-only-treated pericardium: calcium, 228.32 +/- 37.39 mg g(-1); P < 0.0001). Conceivably, inactivation of unpaired aldehyde moieties present in bioprostheses after exposure to glutaraldehyde by amino compounds followed by blocking the potential binding sites of the graft with a surface modifying agent like heparin would be the key steps in the prevention of calcification and degeneration of glutaraldehyde-treated biological tissue grafts.

Anticoagulant therapy in pregnancy. Report of 54 cases

BACKGROUND

To investigate the adverse effects of anticoagulant therapy during pregnancy in a tertiary care center.

MATERIAL AND METHODS

A prospective study was carried out between 1 January 1977 and 31 December 1994 and included 54 pregnancies in 50 women treated with anticoagulants. In Group I (n=43) oral anticoagulants were replaced for heparin from the sixth until the end of the twelfth week of gestation and acenocoumarol was not substituted. All patients received vitamin K antagonists during the second and third trimesters. Heparin was given after 36 weeks of pregnancy until the tenth day in the postpartum period. Statistical comparisons used Chi square test (with the Yates correction when appropriate) and Student t test.

RESULTS

Mechanical heart valve prosthesis was the most frequent indication (68%). There was one artificial heart valve thrombosis during first trimester in Group I and none in Group II (p=0.45). One spontaneous abortion occurred in each group (p=0.86). Seven cardiac complications (13.7%) occurred during the second and third trimesters. We recorded no thrombotic episode of an artificial heart valve after the first trimester of pregnancy. Hemorrhagic complications occurred in mid-pregnancy (one case=2%) and during peripartum (eight cases=16%). Two maternal deaths occurred in the postpartum period, both were linked with the anticoagulant therapy. There was one coumarin embryopathy (Group II: 9%),but no neonatal mortality.

CONCLUSIONS

(1) Hemorrhagic complications occur among 16% of patients receiving anticoagulant therapy during pregnancy. (2) Delivery and postpartum are the most critical periods.

Pregnancy and bioprostheses: influence on structural valve deterioration

The long-term performance of bioprostheses was evaluated in women 35 years of age or less to determine the influence of pregnancy on structural valve deterioration. Between 1972 and 1992, 237 female patients received 255 biological prostheses. Of the total operations, 53 were performed in patients who experienced pregnancy (P) and 202 in patients who were never pregnant (nonpregnant [NP]). The mean age of the P group was 23.0 +/- 5.8 years (standard deviation) (12 to 34 years) and of the NP group it was 27.1 +/- 6.3 years (8 to 35 years) (p < 0.05). The mean follow-up for the NP group was 6.8 years and for the P group it was 7.9 years. The late mortality was 2.26%/patient-year overall, 2.71%/patient-year for the NP group and 0.89%/patient-year for the P group (p = not significant [NS]). The P group of 52 patients had 94 pregnancies: 70 deliveries (74.5%) and 24 abortions (25.5%) (therapeutic, 14 [15%]). There were a total of 143 valve-related complications (P, 35; NP, 108); the majority for structural valve deterioration (SVD) 43% (109 patients), P 51% (27 patients) and NP 41% (82 patients) (p = NS). The valve-related reoperation rate paralleled the SVD rate at 42% (107 patients), P 51% (27 patients) and NP 40% (80 patients) (p = NS). The overall reoperative mortality rate was 6.0%. The interval from initial implant to reoperation was 99.6 +/- 3.6 months (p = NS groups P and NP).(ABSTRACT TRUNCATED AT 250 WORDS)

Outcome of pregnancy in women with valve prostheses

OBJECTIVE

To study the outcome of pregnancy in women with artificial heart valves treated in major European centres, and to compare the safety and efficacy of different anticoagulant regimens and of mechanical and bioprosthetic valves.

DESIGN

Retrospective study.

METHOD

The information was obtained by questionnaire sent to all major cardiac centres in Europe sending one cardiologist from each centre a covering letter suggesting that the questionnaire be handed on where appropriate to the most relevant colleague.

RESULTS

214 pregnancies were reported in 182 women; 151 pregnancies in 133 women with mechanical valves, and 63 pregnancies in 45 women with bioprostheses. Most women were in New York Heart Association class I or II and in sinus rhythm. 150 women with mechanical valves and 11 (17%) with bioprostheses received anticoagulants during pregnancy. One patient with an aortic valve prosthesis refused to take anticoagulants. Including the spontaneous abortions reported as well as the therapeutic abortions 83% of the pregnancies in women with bioprostheses and 73% in those with mechanical valves resulted in a healthy baby, full term or premature, who did well (NS). The incidence of stillbirths (3% and 6%) and of reported spontaneous abortions are excluded (because they are unlikely to have been fully reported), the success rate was 91% for women with bioprosthetic valves and 84% for women with mechanical valves (NS). 114 (53%) of the women had taken warfarin for some part of the pregnancy (46 (40%) of these during the first trimester) but there were no embryopathies. There were 13 valve thromboses (four fatal), eight embolic events (two fatal), and seven bleeds in women with mechanical valves. Most of these complications occurred with heparin but fatal aortic valve thrombosis occurred in the one woman who refused anticoagulant treatment out of the 151 women with mechanical valves. There were no maternal deaths in the bioprosthesis group but in 17/49 (35%) of these valves functional deterioration led to urgent replacement during pregnancy (two) or soon after.

CONCLUSIONS

The outcome of pregnancy was similar for women with mechanical valves or bioprostheses. Warfarin treatment was safe and effective and was not associated with embryopathy. Heparin treatment was associated with more thromboembolic complications and more bleeding complications. Bioprostheses deteriorate rapidly during pregnancy.

Pregnancy in patients with prosthetic heart valves: the effects of anticoagulation on mother, fetus, and neonate

Maternal and fetal complications in a consecutive series of 60 pregnancies in 49 patients with prosthetic heart valves were prospectively evaluated. Group 1 consisted of 40 pregnancies in 31 patients who were taking oral anticoagulants. No oral anticoagulation was used in 20 pregnancies in 19 patients (group 2). In group 1 there were three instances of acute valvular thrombosis during the 35 pregnancies in patients with mechanical prostheses, with two maternal deaths. There were two episodes of cerebral embolism, one in group 1 and one in group 2. Patients with isolated aortic valve replacement had fewer maternal complications (2 of 13) than patients with isolated mitral valve replacement (15 of 42) without statistical significance. Severe bioprosthesis dysfunction occurred in 4 of 25 pregnancies (one rupture and three stenosis) with two maternal deaths, one in the puerperium and the other in the postoperative period of cardiac surgery during pregnancy. When analyzing obstetric events we observed seven spontaneous abortions and one hydatidiform mole. All spontaneous abortions occurred in group 1. The incidences of prematurity and low birth weight were significantly higher in group 1 than in group 2 (46.6% vs 10.5%, p less than 0.05, and 50% vs 10.5%, p less than 0.05, respectively). Moreover, there was a significant association between prematurity and the mother's New York Heart Association functional class (61.5% in classes III and IV vs 22.2% in classes I and II, p less than 0.05). There were five neonatal deaths, all in group 1 (p = NS vs group 2). Three infants had warfarin-related congenital defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Extended follow-up of the standard Hancock porcine bioprosthesis

We have reviewed 665 patients in whom the standard Hancock porcine bioprosthesis (HPB) was used for aortic (AVR = 173), mitral (MVR = 437), and mitral and aortic (MAVR = 55) valve replacement in the time interval from 1970 to 1983. After AVR, HPB-related deaths occurred in 24 patients (1.7% +/- 0.4% per patient-year); 11 had thromboembolic episodes (0.8% +/- 0.2% per patient-year), 6 hemorrhages related to anticoagulants (0.4% +/- 0.2% per patient-year), 9 endocarditis (0.7% +/- 0.2% per patient-year), 7 prosthetic leak (0.5% +/- 0.1% per patient-year), and 59 structural deterioration (4.3% +/- 0.6% per patient-year). At 16 years, actuarial survival is 40% +/- 6%, freedom from thromboembolic episodes 89% +/- 4%, from hemorrhages 90% +/- 5%, from endocarditis 94% +/- 2%, from prosthetic leak 95% +/- 2%, and from structural deterioration 36% +/- 6%. After MVR, HPB-related deaths occurred in 64 patients (1.6% +/- 0.2% per patient-year); 68 had thromboembolic episodes (1.7% +/- 0.2% per patient-year), 28 hemorrhages (0.7% +/- 0.1% per patient-year), 12 endocarditis (0.3% +/- 0.1% per patient-year), 9 prosthetic leak (0.2% +/- 0.1% per patient-year), and 158 structural deterioration (4.0% +/- 0.3% per patient-year). At 18 years, actuarial survival is 33% +/- 4%, freedom from thromboembolic episodes 57% +/- 13%, from hemorrhages 81% +/- 6%, from endocarditis 91% +/- 4%, from prosthetic leak 98% +/- 1%, and from structural deterioration 18% +/- 5%.(ABSTRACT TRUNCATED AT 250 WORDS)

[Maternal mortality due to heart disease]

A retrospective study on maternal mortality in pregnant women with cardiac disease over a period of eleven years (January 1979 to December 1989) was undertaken. The objective was an analysis of the main aspects of this association. Cardiac disease was diagnosed in 694 patients (4.2%) of a total of 16,423 admitted to the Obstetrics Department of the Escola Paulista de Medicina. As for etiology, rheumatic disease (52.3%); Chagas's disease (19.3%) and congenital disease (8.1%) were the most frequent causes. There were 51 maternal deaths, according to FIGO's definition (1967), corresponding to a maternal mortality rate of 428.2/100,000 livebirths during the same period. Twelve of these maternal deaths were due to cardiac disease (maternal mortality rate of 100.8/100,000 livebirths). The statistical analysis identified the following aspects associated with maternal mortality among patients with cardiac disease: primigravida, lack of adequate prenatal care, and cardiac surgery performed previously to and/or during pregnancy. Congestive heart failure with pulmonary edema (41.7%) and thromboembolism (25.0%) were the most frequent causes of maternal death among patients with cardiac disease. The NYHA functional classification was not a good parameter for pregnancy prognosis: eleven patients (91.7%) were considered as belonging to the favorable group before they became pregnant. Most maternal deaths occurred during the first 72 hours after delivery. Therefore, this period was considered most critical for maternal mortality in patients with cardiac disease. No relation-ship was found among the factors: maternal age, race, marital status, delivery and maternal mortality among patients with cardiac disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Pregnancy and its complications after cardiac valve replacement

The outcome of 64 pregnancies in 40 women who conceived after cardiac valve replacement were reviewed. Fetal wastage was 53.2% (25/47) in coumarin administered pregnancies, 36.4% (4/11) using heparin and 16.7% (1/6) without anticoagulants. Two fetal malformations were noted in coumarin administered pregnancies. There were two maternal deaths. Maternal morbidity due to antenatal bleeding, atrial fibrillation, thromboembolic episodes and cardiac failure were found to be 20.0% (8/40), 17.5% (7/40), 10.0% (4/40) and 10.0% (4/40), respectively.

Managing the pregnant patient with heart disease

Pregnancy and its associated hemodynamic challenge presents potential risks to the patient with cardiac disease, whether acquired or congenital. The hematologic changes which occur during pregnancy include alterations in blood volume, hematocrit, and blood viscosity. There are also alterations in cardiac output and regional blood flow patterns. These hemodynamic alterations are associated with signs and symptoms which can be impressive yet benign, or can suggest poor outcome, depending on the underlying cardiovascular disorder. The clinician is faced with the sometimes difficult task of differentiating the benign from the dangerous while making appropriate management decisions. In this article, diagnosis and current management of many of the more common acquired and congenital cardiac abnormalities are discussed as they pertain to the gravid female. The effects of common cardiovascular medications in pregnancy are also briefly reviewed.

Maternal and fetal sequelae of anticoagulation during pregnancy in patients with mechanical heart valve prostheses

Previous reports indicate an increased risk of thrombotic and embolic events in patients with mechanical heart valve prostheses during pregnancy. We prospectively followed 50 pregnancies in 49 patients with 62 cardiac prostheses from presentation at the antenatal clinic through the remainder of the pregnancy. Of the 60 mechanical prostheses, 39 were Medtronic-Hall, 7 St. Jude Medical, 7 Starr-Edwards and 7 Björk-Shiley. Forty-three patients were in New York Heart Association functional class I or II and 6 were in functional class III or IV. Forty-five patients were in sinus rhythm and 4 had chronic atrial fibrillation. All patients received warfarin during the first and second trimesters. Forty-one pregnancies proceeded beyond 28 weeks. In 23 of these (group I) warfarin was replaced with heparin at 36 weeks gestation. In the remaining 18 (group II) warfarin was not substituted owing to premature onset of labor. The target prothrombin ratio (international normalized ratio) in patients receiving warfarin was 2.0 to 2.5. The partial thromboplastin time was maintained at 1.5 to 2.5 times the control value in patients receiving heparin. Eleven patients received dipyridamole plus warfarin for the duration of pregnancy. There were no maternal thromboembolic complications or deaths associated with pregnancy. Antepartum hemorrhage occurred in 1 patient at 35 weeks gestation. One patient (group I) experienced peripartum hemorrhage. All patients were hemodynamically stable before delivery, but 2 developed pulmonary edema during labor. The mean fetal birth weight was low (2.54 +/- 0.98 kg). There were 9 abortions (18%), 7 stillbirths (14%), 2 neonatal deaths (4%) and 2 instances of warfarin embryopathy (4%).(ABSTRACT TRUNCATED AT 250 WORDS)

The standard Hancock porcine bioprosthesis: overall experience at the University of Padova

All patients undergoing aortic (AVR, n = 196), mitral (MVR, n = 502), and mitral-aortic (MAVR, n = 71) valve replacement with a standard Hancock porcine bioprosthesis (HPB) from 1970 to 1983 were reviewed. A total of 665 patients discharged were followed for 5,099 patient-years with an actuarial survival at 15 years of 52% +/- 4.5%, for MVR, 37% +/- 14% for AVR, and at 12 years of 52 +/- 7.4% for MAVR. Embolic episodes occurred in 9 patients after AVR (0.7% +/- 0.2% pt-yr), in 61 after MVR (1.7% +/- 0.2% pt-yr), and in 6 after MAVR (1.7% +/- 0.7% pt-yr); actuarial freedom from emboli at 15 years is 91% +/- 3.5% after AVR, 79% +/- 14% after MVR, and at 12 years is 87% +/- 5% after MAVR. Reoperation because of primary tissue failure (PTF) was performed in 47 patients with AVR (3.9% +/- 0.5% pt-yr), 91 with MVR (2.6% +/- 0.3% pt-yr), and in 13 with MAVR (4.1% +/- 1.1% pt-yr); actuarial freedom from PTF at 15 years is 41% +/- 5.5% after MVR, 37% +/- 10% after AVR, and at 12 years is 49% +/- 13% after MAVR. After AVR and MVR, freedom from PTF is significantly better for patients over 50 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Performance of the Hancock porcine bioprosthesis following aortic valve replacement: considerations based on a 15-year experience

All patients undergoing isolated aortic valve replacement with a standard Hancock porcine bioprosthesis (PB), from 1970 to 1983, were reviewed. There were 196 patients, 162 male and 34 female patients, with a mean age of 48 +/- 12 years. Operative survivors were followed up from 3 to 15.6 years (mean follow-up, 6.6 +/- 1.5 years), with a cumulative follow-up of 1,140 patient-years, being 100% complete. Actuarial survival was 51 +/- 15% at 14 years. Eight patients sustained systemic embolic episodes (0.7 +/- 0.2%/patient-year); actuarial freedom from emboli is 89.4 +/- 4.3% at 14 years. Reoperation was performed in 53 patients: in 6 because of endocarditis (0.5 +/- 0.2%/patient-year), in 7 because of perivalvular leak (0.6 +/- 0.2%/patient-year), and in 40 because of PB primary tissue failure (3.5 +/- 0.5%/patient-year). Actuarial freedom from PB-related deaths, PB failure, and overall PB-related complications at 14 years was 66.3 +/- 19, 34.3 +/- 11, and 30 +/- 10%, respectively. This long-term experience shows that the performance of the Hancock PB appears satisfactory up to 8 years, while it progressively deteriorates beyond 10 years because of the impact of primary tissue failure on valve durability, justifying the restriction of its use in the aortic position in selected patients.

Incidence of primary tissue valve failure in porcine bioprosthetic heart valves

This report provides retrospective follow-up data on 324 consecutive patients who received a Hancock-I porcine valve in the aortic or the mitral position, or in both positions, between June, 1974, and December, 1976. This analysis included 319 valves (193 mitral, 126 aortic) available for study of the incidence of primary tissue valve failure after 10 to 12.5 years of follow-up. Of the 319 prostheses at risk, 114 instances of primary tissue valve failure occurred. Seventy-three of the failed valves were in the mitral position, and 41 were in the aortic position. The calculated actuarial probability of freedom from primary tissue valve failure was 52 +/- 5% for the mitral and 58 +/- 6% for the aortic prostheses at 12.5 years of follow-up. For patients older than 40 years at the time of operation, the rate of freedom from primary failure was 68 +/- 8% and 55 +/- 6% for aortic and mitral prostheses, respectively, at 12.5 years. Comparison of both actuarial curves disclosed no meaningful difference. However, a tendency toward greater failure rate was observed in the mitral prosthesis group.

Thrombotic and bleeding complications of prosthetic heart valves

A review of articles published since 1979 indicates that thrombotic and bleeding complications account for about 50% of valve-related complications in patients with bioprosthetic aortic and mitral valves and for approximately 75% of the complications in patients with mechanical valves. Although compromised by lack of standard definitions and by variability in reporting and follow-up, the data suggest that the linearized rate of both thrombotic and bleeding complications in patients with aortic bioprostheses is approximately half that for aortic mechanical prostheses (2% versus 4%), but is approximately equal for both bioprostheses and mechanical valves in the mitral position (approximately 4%), and for mechanical and bioprosthetic aortic and mitral valves in combination. However, linearized rates for fatal thrombotic and bleeding events are two to four times higher in patients with mechanical prostheses. The adequacy of warfarin anticoagulation is the most important factor affecting thrombotic and bleeding complications in patients with mechanical valves and over shadows the dubious importance of other phenomena such as atrial fibrillation and left atrial thrombus. Short-term warfarin anticoagulation or the use of long-term platelet inhibitors, or both, do not appear to reduce the incidence of thrombotic complications in patients with aortic bioprostheses but increase bleeding. For mitral bioprostheses, the postoperative use of warfarin for three months or aspirin indefinitely is as effective in preventing thromboembolism as long-term warfarin. Acute prosthetic valve endocarditis is associated with a 13 to 40% incidence of thrombotic complications. Likewise, the recurrence rate of cerebral emboli is high (20-30%) in patients with prosthetic valves who are not anticoagulated. Bioprostheses are strongly preferred for women who wish to bear children; fetal wastage occurs in 25 to 30% of pregnant women with mechanical heart valves who receive either warfarin or heparin, or a combination of the two. Heparin, however, greatly increases the risk of maternal bleeding. In children, the efficacy of platelet inhibitors without warfarin anticoagulation is unproven; nearly all serious strokes occur when warfarin is omitted; and permanent disability from warfarin-related bleeding is rare. All prosthetic cardiac valves initiate coagulation and affect the dynamic equilibrium between activated procoagulants and endogenous anticoagulants. Warfarin is the only available oral exogenous anticoagulant.(ABSTRACT TRUNCATED AT 400 WORDS)

Cardiac valve prostheses: pathological and bioengineering considerations

Cardiac valve replacement with mechanical prosthetic or bioprosthetic devices enhances patient survival and quality of life. Nevertheless, prosthesis-associated complications are frequent and contribute significantly to outcome. Thromboembolic complications are the most important problems in patients with mechanical valves, necessitating chronic anticoagulation in all patients receiving them. In contrast, patients with bioprosthetic valves, composed of chemically treated animal tissues, generally do not require anticoagulants. However, bioprostheses fail frequently by degeneration, especially that involving cuspal calcification. This paper reviews the pathological and bioengineering considerations in the selection of cardiac prosthetic valves and the management of patients who have received these devices. The significance, morphology, and pathogenesis of the observed major complications and other alterations during function are described in detail. Contemporary investigative trends are summarized, including studies of inhibition of mineralization and other degenerative changes in bioprostheses, improved design rigid mechanical valves with pyrolytic carbon occluders and the development of central-flow, flexible polymeric leaflet valves.

Inhibition by diphosphonate compounds of calcification of porcine bioprosthetic heart valve cusps implanted subcutaneously in rats

Calcification limits the long-term success of heart valve bioprostheses fabricated from glutaraldehyde cross-linked porcine aortic valves. The pathophysiology of calcification of bioprostheses has been studied experimentally with subcutaneous implants of the valve cusps in rats; in this preparation, the accumulation of calcific deposits is biochemically and morphologically identical to that occurring in clinical specimens. The objective of the present study was to determine whether mineralization of bioprosthetic valve cusps (BC) subcutaneously implanted in 3-week-old male rats could be inhibited through the use of diphosphonate compounds. Ethanehydroxydiphosphonate (EHDP), administered by daily subcutaneous injection (25 mg/kg/24 hr) for 21 days inhibited calcification (BC Ca++ = 154.9 +/- 4.1), but caused somatic growth retardation and disruption of epiphyseal development. However, local administration of EHDP by osmotic pump (5 mg/kg/24 hr) implanted in direct contact with the cuspal tissue for 14 days prevented BC calcification (BC CA++ = 4.3 +/- 0.7) without adverse effects. Furthermore, EHDP given by osmotic pump had a prolonged effect on reducing calcification, as demonstrated by implants harvested 21 days (BC CA++ = 12.2 +/- 6.4) after the drug supply was exhausted. Finally, BC preincubated in aminopropanehydroxydiphosphonate for 24 hr before 21 day implantation underwent less calcification (CA++ = 24.2 +/- 7.4) than control valves (BC CA++ 126.6 +/- 7.5) with no adverse effects. We conclude that diphosphonates inhibit BC calcification, and that adverse effects of systemic therapy can be avoided by local administration.

Isolated mitral valve replacement with the Hancock bioprosthesis: a 13-year appraisal

Four hundred seventy-six patients underwent isolated mitral valve replacement (MVR) with the glutaraldehyde-preserved porcine Hancock bioprosthesis from March, 1970, through December, 1981. There were 312 female and 164 male patients ranging in age at operation from 9 to 68 years (average, 53 years). Associated surgical procedures were performed in 35 patients. Hospital mortality was 13%, the main cause of death being low-output syndrome. The survivors were followed from 1.6 to 13.2 years (mean, 5.2 years). Cumulative duration of follow-up is 2,180 patient-years and is 97% complete. Overall late mortality is 3.1 +/- 0.3% per patient-year, and actuarial survival is 73.8 +/- 3.4% at 13 years. Embolic accidents occurred in 45 patients and were fatal in 13; the linearized incidence of postoperative systemic thromboemboli is 2.1 +/- 0.3% per patient-year. Reoperation was necessary in 49 patients: in 4 because of valve endocarditis, with 3 deaths; in 6 because of perivalvular leak, with no deaths; in 2 because of left atrial thrombosis; and in 37 because of valve dysfunction due to primary tissue failure, caused mainly by calcific degeneration of the tissue, with 5 operative deaths. Actuarial freedom from primary tissue failure is 58 +/- 6.6% at 13 years. Extended follow-up after MVR with the Hancock bioprosthesis confirms the satisfactory performance and low thrombogenicity of this device up to 13 years after operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Congestive heart failure in valvular heart disease in pregnancies with and without valvular prostheses and anticoagulant therapy

The course and complications of pregnancies in 46 patients with valvular disease and congestive heart failure with or without valve prostheses are described. In group I consisting of 33 women without valve replacement and without anticoagulant therapy one thromboembolic event was seen, emergency closed or open heart surgery was necessary five times. One still-birth happened after open heart surgery. In group II, of 13 patients with prosthetic valve replacement and anticoagulation therapy there was no thromboembolism, but 2 spontaneous abortions and 2 premature stillbirths; 2 fetuses died after delivery, 3 had congenital abnormalities. Pregnancies in patients with valvular disease and congestive heart failure can be sustained relatively safely for the mother, even if emergency heart surgery becomes necessary. Heart surgery and anticoagulation treatment carry a higher risk for the fetus. Uterine blood loss is not increased, if coumadine treatment is switched to heparin administration shortly before delivery.