Light and electron microscopic localization of atrial natriuretic peptide in the heart of spontaneously hypertensive rat.

Atrial natriuretic peptide (ANP) is a newly discovered peptide hormone present mainly in the atria. We investigated the occurrence and distribution of ANP immunoreactivity in the myocardiocytes of the ventricles of spontaneously hypertensive rats by use of immunocytochemistry at both light and electron microscopic level. ANP immunoreactivity was found in the specific granules in the cytoplasm of the cardiocytes in the subendocardium and the myocardium of the ventricles, as well as in the atria. The specific granules found in the ventricles of hypertensive rats were similar in size, shape, and ANP immunoreactive content to those in the atria. The abundance of ANP immunoreactivity in the left ventricle is greater than that in the right, and appears to increase with increasing severity of hypertension. Conversely, the overall content of ANP in the atria of hypertensive rats was decreased when compared with that in age-matched normotensive rats. The present findings indicate that ventricles may become a major source for ANP synthesis and release during hypertension, and may play important roles in cardiac endocrine pathology and cardiac hypertrophy.

Successful correction of total anomalous pulmonary venous connection in a 2.5 kilogram premature neonate.

A 16 day old 2.5 kg premature infant with total anomalous pulmonary venous drainage to the coronary sinus was successfully treated with use of profound hypothermia and total circulatory arrest. To the best of our knowledge, this neonate is the smallest to successfully undergo correction of this anomaly. A plea is made for a more aggressive approach in early recognition and assessment of these critically ill infants, followed by early surgical correction.

Thrombosis of an aortic porcine xenobioprosthesis associated with familial antithrombin III deficiency.

Thrombosis of a porcine xenobioprosthesis in the aortic position associated with antithrombin III deficiency has not been reported. Admittedly a rare coagulation abnormality, it should be suspected in patients with previous tendencies or family history toward spontaneous thrombosis, especially in those with Scandinavian ancestry. Special precautions should be taken if a cardiac operation becomes necessary.

Actuarial survival, freedom from reoperation, and other events after repair of atrioventricular septal defects.

Repair of an atrioventricular septal defect was performed in 134 patients from 1973 to 1985. Interventricular communication was present in 54 (40%) and none was present in 80 (60%). There were 12 hospital deaths (9%; 70% confidence limits 6%-12%). Earlier date of operation (p = 0.03) and younger age at repair (p = 0.005) were incremental risk factors for hospital death after repair of partial atrioventricular septal defect. Smaller size (p = 0.003) and longer cross-clamp time (p = 0.002) were risk factors for hospital death in those patients with complete atrioventricular septal defect. Higher preoperative pulmonary vascular resistance was a risk factor for death in both groups (p = 0.007). The 10 year actuarial survival rate was 82% overall. Increasing preoperative severity of left atrioventricular valve incompetence was not a risk factor for early (p = 0.001) or late (p = 0.002) death. The 10 year actuarial freedom from reoperation after repair of partial atrioventricular defects was 85%, and it was 68% for complete atrioventricular defects (p = 0.06). We conclude that the intermediate term results after repair of atrioventricular septal defects are good. Incompetence of the left atrioventricular valve has apparently been neutralized as a risk factor for hospital death in this series. However, the durability of the repair has been disappointing. A policy of earlier repair has been adopted and should improve hospital mortality and permit better preservation of the atrioventricular valve structures with resultant improved late term functional status.

Determination of the need for a ventriculotomy in the repair of tetralogy of Fallot.

Fifty-two patients with tetralogy of Fallot underwent repair between March 1985 and July 1987. The repair was made without a ventriculotomy whenever feasible. There were no (0%) early or late-phase deaths (70% confidence limits 0% to 3.6%). Operative reports and preoperative angiocardiograms were retrospectively reviewed to delineate determinants for operative approach. Two distinct morphologic subgroups were observed angiographically and confirmed intraoperatively. Thirty-two patients (62%) had severe hypertrophy of the infundibular septal structures. Each of these 32 underwent transatrial and transpulmonary repair of the infundibular stenosis, and 12 of them also required a limited ventriculotomy to enlarge a hypoplastic pulmonary valve anulus. The other 20 patients (38%) were found to have hypoplasia and not hypertrophy of the infundibular septum. Each of these required a formal transventricular approach to the repair with an infundibular patch inserted to relieve the infundibular stenosis. Right ventricular/left ventricular systolic pressure ratios after repair were not different between the groups (p = 0.79). In conclusion, tetralogy of Fallot was satisfactorily repaired by means of a transatrial and transpulmonary approach in two thirds of these patients. The avoidance of a ventriculotomy to accomplish repair may be suggested preoperatively by selective angiocardiogram and confirmed by intraoperative assessment. These findings have important implications for the development of treatment protocols.

Spontaneous closure of paravalvular leak after mitral valve replacement.

Complications after prosthetic valve replacement may be multiple. In biologic valves, valve detachment and cusp perforation may occur. If this is of significant magnitude, reoperation may be required. This report describes recurrent mitral regurgitation after mitral valve replacement with a Hancock porcine xenograft. The regurgitation subsided spontaneously three months later. We felt that a paravalvular leak closed, with progressive fibrosis and tightening of the annulus. Functional results in this patient were excellent.

Safety of the right atrial approach for combined mitral and tricuspid valve procedures.

Patients undergoing operation for combined mitral and tricuspid valvular disease may have the repair performed through the right atrium and the interatrial septum. Although the transseptal method is an established procedure, recent reports have stressed the disadvantages of this operation and underscored the risk of the development of complete atrioventricular dissociation with this technique. A review of our results with this approach confirms the efficacy and safety of this method. The surgical protocols used are described.

Orthoterminal correction of coexisting d-transposition of the great arteries, subpulmonary stenosis, and a complete form of atrioventricular canal.

This report outlines orthoterminal correction in an 8-year-old boy with coexisting d-transposition of the great arteries (d-TGA), subpulmonary stenosis, and a complete form of atrioventricular canal (CAVC). The repair consisted of covering the tricuspid valve and atrial part of the atrioventricular canal with a Dacron patch and inserting a valve-containing conduit between the then isolated right atrium and the pulmonary artery to create a venous outlet. The patient's exercise tolerance has improved remarkably. The arterial oxygen saturation has risen from 86 to 90 per cent. A plea is made to expand the indications for orthoterminal correction to patients in whom the severity of the heart malformation precludes application of well-established methods of surgical repair.

Mechanical testing of cryopreserved aortic allografts. Comparison with xenografts and fresh tissue.

Reports indicate that cryopreserved aortic valve allografts have a better long-term survivability than other bioprostheses, such as the porcine xenograft. Unlike xenografts, allograft valves do not require treatment with glutaraldehyde and may therefore retain much of their original mechanical function. The effects of cryopreservation on the mechanical integrity of collagen fibers and mucopolysaccharides, however, are still largely unknown. We therefore compared the mechanical behavior of cryopreserved allograft leaflet material to that of fresh tissue and xenografts by measuring their bending stiffness (nine strips of tissue) and their uniaxial tensile stress/strain and stress/relaxation behavior (six strips of each tissue type). The bending tests showed no significant difference between the pliability of cryopreserved allografts and fresh pig aortic valve tissue, but the xenograft material was significantly stiffer than both (p less than 0.001). The mean circumferential tensile elastic moduli of the allografts, fresh tissue, and xenografts at a stress of 300 kPa were 9.1 +/- 5.4 MPa, 13.0 +/- 1.7 MPa, and 12.5 +/- 3.0 MPa, respectively, and were not significantly different from each other. We also found that the transition from a low to a high modulus on the stress/strain curves, a measure of extensibility, occurs at 23%, 22%, and 12% strain for the three materials. There was no significant difference between the allograft and the fresh tissues, but the xenograft material was less extensible than the other two (p less than 0.001). The xenograft tissue also had significantly lower rates of stress relaxation than the other two materials (p less than 0.005). Thus no detectable differences were found between the mechanical behavior of the cryopreserved allograft aortic leaflets and fresh tissue, whereas the xenograft material was less extensible and less capable of relaxing than both the allograft and fresh tissue. The ability of allografts valves to respond to tensile and flexural stresses in a manner similar to that of the natural aortic valve may therefore contribute to their good in vivo survivability.

The pericardial valve in the aortic position ten years later.

To assess the behavior of the pericardial valve at 10 years after implantation, the cases of 240 patients who had undergone aortic valve replacement with the standard Ionescu-Shiley (Shiley, Inc., Irvine, Calif.) bovine pericardial valve between February 1977 and December 1983 were reassessed. Follow-up of the 224 hospital survivors was 99.6% complete. Fifty-seven valve-related events occurred. Fourteen were thrombotic events (1.2%/patient-year), 28 were intrinsic tissue failures (2.4%/patient-year), 13 were cases of prosthetic valve endocarditis (1.1%/patient-year), and 2 were paravalvular leaks (0.17%/patient-year). The linearized rate for death, reoperation, or both resulting from valve-related events was 3.6%/patient-year. Time-related hazard function for the instantaneous risk of death and/or reoperation resulting from valve-related events demonstrated an exponential increase after 80 months. These data, in conjunction with our previous reports on the histologic changes in pericardial collagen and the incidence of calcification (26/28), should be considered regarding new and future generations of pericardial bioprostheses. Although this device provides good hemodynamics and carries a low incidence of thromboembolism, it has a limited durability. New generations of pericardial valves may have improved structural features, but the behavior of glutaraldehyde-fixed, formaldehyde-stored bovine pericardium as currently selected and prepared is unlikely to change.

Factors determining in-hospital or late survival after aortic valve replacement.

To ascertain incremental risk factors for in-hospital and late mortality of patients undergoing AVR with the bovine pericardial valve, multiple variables were analyzed in a group of 240 patients undergoing AVR between 1977 and 1983. Follow-up totaled 12,023 patient-months (mean, 52.7 +/- 1.7 patient-months) and was 100 percent complete. Univariate analysis of incremental risk factors for in-hospital mortality identified the following: age over 60 years (p = 0.015); and advanced preoperative NYHA class (p = 0.003). Multivariate analysis of risk factors for in-hospital mortality identified the following: age (p = 0.038); NYHA class (p = 0.018); and year of operation (p = 0.049). Incremental risk factors for late mortality were identified as age (p = 0.003), year of operation (p = 0.003), concomitant procedure (p = 0.047), and valvular lesion (regurgitation) (p = 0.053). Actuarial survival of patients (+/- SE) was 87 +/- 2 percent, 75 +/- 3 percent, and 61 +/- 5 percent at 2, 5, and 8.7 years, respectively. The actuarial survival of patients experiencing valve-related events was 62.6 +/- 10.1 percent at 8.7 years, compared to 55.4 +/- 7 percent for those who did not (p = 0.38).

Randomized clinical trial of fibrin sealant in patients undergoing resternotomy or reoperation after cardiac operations. A multicenter study.

A multicenter study was conducted to test the efficacy and safety of fibrin sealant as a topical hemostatic agent in patients undergoing either reoperative cardiac surgery (redo) or emergency resternotomy. A total of 333 patients from 11 centers in the United States were included in the study. Patients were randomly assigned to initially receive the fibrin sealant or a conventional topical hemostatic agent when such was required during an operation. The end point used to evaluate the agent's efficacy was local hemostasis, the number of bleeding episodes controlled within 5 minutes. The fibrin sealant group from the prospective study was compared with historical matched control subjects for postoperative blood loss, need for resternotomy, blood products received, and hospital stay. It was also compared with historical nonmatched control subjects for the incidence of resternotomy and mortality. The results showed a 92.6% success rate for fibrin sealant in controlling bleeding within 5 minutes of application, compared with only a 12.4% success rate with conventional topical agents (p less than 0.001). Fibrin sealant also rapidly controlled 82.0% of those bleeding episodes not initially controlled by conventional agents. High-volume postoperative blood loss was significantly less (p less than 0.05) in the fibrin sealant group than in the matched controls. Additionally, resternotomy rates after redo operations were significantly lower in the fibrin sealant group (5.6%) than in the nonmatched historical control group (10%) (p less than 0.0089). There were no significant differences in hospital stay or blood products received between the fibrin sealant group and matched historical controls and no difference in mortality between the fibrin sealant group and nonmatched historical controls. There were no documented instances of adverse reactions, transmission of viral infection (hepatitis B, non-A/non-B hepatitis), or human immunodeficiency virus seroconversion. This study shows that fibrin sealant is safe and highly effective in controlling localized bleeding in cardiac operations. Fibrin sealant reduces postoperative blood loss and decreases the incidence of emergency resternotomy. These findings make fibrin sealant a valuable hemostatic agent in cardiac surgery.

Tricuspid valve operations in 530 patients. Twenty-five-year assessment of early and late phase events.

From Jan. 1, 1961, through Dec. 31, 1987, 530 patients underwent an intracardiac operation that included a tricuspid valve procedure. The tricuspid valve was repaired in 351 patients (66%) and replaced in 179 (34%). Mean age was 56.9 years. Risk factors associated with tricuspid valve replacement included tricuspid stenosis (p = 0.02), jugular venous distention (p = 0.04), previous operation (p = 0.05), and angiographic severity of tricuspid valve incompetence (p less than 0.001). There were 78 hospital deaths (15%). Risk factors for hospital death included previous operation (p = 0.03), male gender (p = 0.03), hepatomegaly (p = 0.03), De Vega or Carpentier annuloplasty (repair group only), (p = 0.01), and older age at operation (p = 0.06). Ninety-eight percent of the patients were followed up. There were 185 late deaths (41%). The actuarial survival rate was 20% at 180 months. Risk factors for late death included male gender (p = 0.03), hepatomegaly (p = 0.04), and lack of postoperative warfarin therapy (p less than 0.001). Actuarial freedom from reoperation was 25.5% at 180 months. There was no difference in reoperation rates (p = 0.10) or survival (p = 0.42) whether the tricuspid valve had been repaired or replaced. We conclude that the requirement for surgical treatment of tricuspid valve insufficiency in patients with multivalvular disease constitutes a high risk group for cardiac surgery. Preoperative variables may predict the result of tricuspid valve replacement. Tricuspid valve replacement may be performed with the expectation of a low risk of valve-related events.

Pulmonary artery balloon counterpulsation for right ventricular failure after right ventriculotomy in the swine.

To assess the efficacy of intrapulmonary balloon counterpulsation in the management of right ventricular failure after right ventriculotomy, we undertook an experimental study in a swine model. To mimic the clinical settings more closely, (1) we left the automatic control of the heart intact (2) did not use cardiopulmonary bypass to support the left side of the heart, and (3) induced right ventricular failure by means of a generous surgical incision (50% to 70% of the anterior wall) of the right ventricle. The criteria set for right ventricular failure were (1) 50% increase in right ventricular end-diastolic pressure, (2) 30% decrease in mean arterial pressure, and (3) 30% decrease in cardiac output. Right ventricular failure was attained in all animals studied: A 230% increase in right ventricular end-diastolic pressure, a 43% decrease in cardiac output, and a 34% decrease in mean arterial pressure were evident after the right ventriculotomy. A specially designed intrapulmonary balloon catheter (Datascope Corp., Oakland, N.J.) was placed into the left pulmonary artery through the right ventricular outflow tract. A Datascope console was used for counterpulsation. Effects of counterpulsation for 40 minutes in a 1:1 mode were assessed after surgical induction of right ventricular failure in 14 swine. Each animal served as its own control. The mean hemodynamic changes are outlined: Right ventricular end-diastolic pressure decreased by 48.9% (p = 0.01). Mean arterial pressure increased by 68.8% (p = 0.01) and cardiac output by 44.2% (p = 0.01). Histologic studies disclosed no morphologic damage to the pulmonary artery or valve in the specimens analyzed. In addition, these results were compared with those in a second group of seven swine in which right ventricular failure was induced by right ventriculotomy and a balloon was placed into the left pulmonary artery but not activated. These results of short-term counterpulsation should be evaluated in a longer term model so as to mimic more closely the clinical setting. If the hemodynamic benefits are duplicated, intrapulmonary balloon counterpulsation should be considered as a simple, effective device when right ventricular failure develops after right ventriculotomy. It effectively improves right ventricular function without damaging the pulmonary artery or valve.

The risk of thromboembolism and hemorrhage following mitral valve replacement. A comparative analysis between the porcine xenograft valve and Ionescu-Shiley bovine pericardial valve.

To ascertain the risk of thromboembolism and anticoagulant-related hemorrhage following mitral valve replacement with bioprostheses, an 8 year retrospective study between two groups of patients was analyzed. Group I included 206 patients undergoing mitral valve replacement with porcine xenograft valves. They were placed on a regimen of long-term oral anticoagulation (greater than 8 weeks, mean 6 months). Follow-up was 524.3 patient-years, mean 30.5 months. There were 24 thromboembolic events (4.6% per patient-year), four of which were fatal. Actuarially, 80.7% +/- 4.3% are free of thromboembolism at 8 years. There were 12 instances of major bleeding episodes, for a linearized incidence of 2.5% per patient-year; two were fatal. Group II included 322 patients undergoing mitral valve replacement with a bovine pericardial valve. They were placed on a program of short-term anticoagulation (6 weeks only). Follow-up was 1,106 patient-years, mean 46.4 months. There were four thromboembolic episodes (none fatal), an incidence of 0.36% per patient-year. Seven bleeding episodes occurred, 0.63% per patient-year; none was fatal. The difference between the groups reached statistical significance (p less than 0.001). The low risk of thromboembolism with the bovine pericardial valve appears to be due to its superior hydraulic characteristics. Use of this valve allows mitral valve replacement without long-term oral anticoagulation and the associated risk of anticoagulant-related hemorrhage.

Charles P. Bailey and Dwight E. Harken--the dawn of the modern era of mitral valve surgery.

The modern era of mitral valve surgery began in the 1940s. I acknowledge the important contributions of two of our country's outstanding pioneers, Charles P. Bailey and Dwight E. Harken. Their trials and tribulations should encourage future generations of cardiac surgeons to proceed with further developments in this field.

Myocardial infarction secondary to calcific embolization: an unusual complication of bioprosthetic valve degeneration.

A patient with coronary artery embolization of calcific material from a degenerated Ionescu-Shiley bovine pericardial bioprosthesis in the aortic position with resultant acute myocardial infarction is described.

Left ventricular wall rupture after mitral valve replacement: report of successful repair in 2 patients.

Left ventricular wall rupture after mitral valve replacement, though uncommon, is a disastrous complication when it does occur. We have experienced this problem in 2 separate instances. Successful treatment was accomplished by suturing a large prosthetic patch over the entire area of laceration and hematoma.

Pulmonary homograft implantation for ventricular outflow tract reconstruction: early phase results.

The pulmonary valve homograft (PH) has been reported to have potential advantages over the aortic valve homograft, including a larger diameter, a thinner wall, and decreased intrinsic calcification. From January 16, 1986, to July 14, 1987, eight consecutive patients underwent repair of congenital cardiac anomalies using a cryopreserved PH. Patients ranged in age from 18 months to 32 years. Diagnoses included tetralogy of Fallot with pulmonary atresia (3 patients); tetralogy with absent pulmonary valve (1 patient); corrected transposition with pulmonic stenosis (1 patient); transposition of the great arteries, ventricular septal defect, and pulmonic stenosis (2 patients); and double-outlet right ventricle with pulmonic stenosis (1 patient). The PH was implanted orthotopically in the patient with absent pulmonary valve, and in the other 7 it was placed as a valved extracardiac conduit. Two of the tetralogy patients with severe bifurcational pulmonary stenosis and another with nonconfluent pulmonary arteries and origin of the left pulmonary artery from a patent ductus arteriosus had their repairs facilitated using the branching pulmonary arterial portion of the PH. There were no hospital or posthospital deaths. Postrepair right ventricular to left ventricular systolic pressure ratios were a mean of 0.35 at 18 hours postoperatively (range, 0.21-0.61). All patients were studied with Doppler and echocardiography after repair. The mean gradient across the PH was 9 mm Hg (range, 2-27 mm Hg), and no pulmonary valve incompetence was present. One patient (12.5%) required reoperation seven months after repair for conduit revision due to compression by the sternum and is now well.(ABSTRACT TRUNCATED AT 250 WORDS)

A method of applying fibrin sealant using an atomizing needle.

A needle modification is described that enables fibrin sealant to be applied as a fine spray to the operative site. The techniques for modification and use of the needle are presented.