Effects of ischemia on sarcoplasmic reticulum and contractile myofilament activity in human myocardium

The effects of global ischemia on the contractile system and on sarcoplasmic reticulum (SR) function were studied by measuring the isometric tension and the SR Ca2+ release activity of chemically skinned cardiac fiber preparations from seven patients undergoing open-heart surgery. Ten minutes of ischemia caused 1) a decrease in the myofilament sensitivity to Ca2+ (expected Ca2+ concentration giving half-maximal tension; from 0.69 +/- 0.04 to 1.38 +/- 0.06 microM, n = 7) and in the cooperativity index (Hill coefficient; from 2.61 +/- 0.45 to 0.92 +/- 0.15, n = 7), 2) a decrease in myosin light chain phosphorylation, and 3) a 300% increase in the threshold caffeine concentration for SR Ca2+ efflux channel activation, with a 30% reduction in the rate of Ca2+ release by caffeine at threshold concentrations and a 23% reduction in the rate of release by 20 mM caffeine. After preincubation with 5 microM trifluoperazine, a calmodulin antagonist, the caffeine threshold of ischemic and control cardiac muscle became comparable. Most changes were reversed by reperfusion, while the caffeine threshold was still two times greater than control. These results indicate that ischemia caused alterations of the cardiac muscle contractile apparatus and the SR that were reversed only after reperfusion.

[Acute rejection: the diagnostic and therapeutic problems]

Acute allograft rejection is still a leading cause of both early and late mortality and morbidity after cardiac transplantation. Besides cell-mediated acute rejection, a "humoral" form exists which is more frequent in younger patients in the early postoperative period, and less likely to respond to the usual therapy. Cyclosporine therapy has deeply affected the clinical, laboratory and histological aspects of acute rejection. Though endomyocardial biopsy remains the most reliable diagnostic tool, other noninvasive procedures are of great value for a final diagnosis; among these are electrocardiography and two-dimensional echocardiography, which are the two elective techniques for post-transplantation follow-up in children. The laboratory and immunological assays, on the contrary, share a very low specificity. In conclusion, the diagnosis of acute rejection is still a clinical one, though supported by laboratory and histological evidence. In our experience, the natural evolution of many mild and mild-moderate rejection episodes toward regression does not support an excessive prophylaxis or an early treatment of symptom-free acute rejection. In addition, treatment of rejection must be personal and specific to each patient.

[Controversies in the selection of donors in heart transplants]

The shortage of ideal donor hearts has led to an increasing number of would-be heart transplant recipients who die while on the waiting list: an extension of the classical donor criteria seems necessary to expand the donor pool. In this paper, the major controversies on donor selection are presented, along with the clinical results obtained in cardiac transplantation with donor grafts not complying with standard criteria. The extension of donor age over 35 years is supported by the decreased incidence of coronary artery disease (CAD) in the Western world. In our experience, the number of donors over 40 years has increased steadily, without concomitant significant increase in postoperative short- and medium-term mortality after cardiac transplantation. The relative importance of CAD risk factors in the older heart donor is to be weighed out on a case-by-case basis. The performance of coronary angiography in 90% of the donor grafts over 50 years has led to more accurate selection. ECG minor alterations and ECHO diagnosed dyskynesias are of uncertain significance. Localized infection, transitory hypotension, brief cardiac arrest and thoracic trauma do not necessarily contraindicate heart donation. The importance of donor/recipient weight mismatch over 20% is critical only in face of high pulmonary vascular resistance. Prolonged dopamine infusion above 10 micrograms/kg/min may predict poorer function outcome. From our data, severe donor dysionemia may be very hazardous. In conclusion, our experience demonstrates that extended donor criteria do not compromise short- and medium-term clinical results of cardiac transplantation. Nevertheless, several controversial aspects of donor graft selection remain open.

A new, noninvasive method to monitor the aging of bioprosthetic valves in the mitral position

Bioprosthetic valves undergo a tissue degeneration of unpredictable onset and amount. This process alters the structure and function of the valve and consequently shortens its lifespan. The echocardiographic technique usually used in the follow-up of these patients does not provide accurate information concerning the amount of prosthesis tissue degeneration. A new technique has been developed based on the spectral analysis of the first heart sound, which enables the evaluation of prosthetic leaflet stiffness. The Young's modulus (E) and stress (s) of the valve leaflets were derived as functions of the inner diameter of the heterograft and its primary vibration frequency, which can be obtained from the frequency spectrum of the first heart sound. Thirty-six patients with a mitral bioprosthetic valve were studied. Fifteen had thickening or calcification, or both, of the valvular leaflets at echocardiographic examination. In patients with a normal valve, E and s showed a good correlation with the duration of implantation (r = 0.909, p < 0.001; and r = 0.828, p < 0.001; respectively). Patients with abnormal leaflets had values of E and s that were greater than the theoretical values expected for their duration of implantation. The procedure is sensitive, accurate and easy to perform, and enables monitoring of the aging of the prosthetic valve and early identification of valve tissue degeneration. Together with echocardiography, this procedure yields a more complete evaluation of prosthetic valves for the follow-up of patients.

Contractile properties and Ca2+ release activity of the sarcoplasmic reticulum in dilated cardiomyopathy

BACKGROUND

We performed a comparative study on Ca2+ release activity of the sarcoplasmic reticulum and calcium sensitivity of contractile apparatus of chemically skinned myocardial fibers obtained from four nonfailing human hearts and 13 excised hearts from patients with idiopathic dilated cardiomyopathy.

METHODS AND RESULTS

Ca2+ sensitivity of contractile apparatus was studied by following the isometric tension developed by chemically skinned myocardial fibers challenged with solutions of decreasing pCa. Ca2+ release from sarcoplasmic reticulum was monitored indirectly by measurement of the isometric tension developed by skinned fibers challenged with caffeine. We observed no significant difference of Ca2+ sensitivity and cooperativity between normal myocardium (pCa50 = 6.00 +/- 0.05; Hill coefficient, nHill = 2.07 +/- 0.10) and dilated cardiomyopathy (pCa50 = 6.03 +/- 0.07; nHill = 2.72 +/- 0.30) when the fibers were stretched to 130% of the resting length. We also found that both in normal myocardium and dilated cardiomyopathy, stretching to 150% of the resting length increased the Ca2+ sensitivity of the contractile system; pCa50 = 6.21 +/- 0.01 and 6.13 +/- 0.04 in normal and dilated cardiomyopathy, respectively, whereas in dilated cardiomyopathy there was a decrease of Hill coefficient with stretching that was not observed in the control group. The caffeine threshold in idiopathic dilated cardiomyopathy was markedly increased compared with the control group, 1.94 +/- 0.27 mmol/l and 0.29 +/- 0.04 mmol/l caffeine, respectively, whereas there were no significant differences in the extent and rate of caffeine-induced Ca2+ release.

CONCLUSIONS

These results indicate that in idiopathic dilated cardiomyopathy there is no alteration of contractile and regulatory proteins; on the contrary, the gating mechanism of the Ca2+ release channel of sarcoplasmic reticulum is abnormal, suggesting a possible involvement of the excitation-contraction coupling in the pathogenesis of this disease. It should also be taken into account, however, that the increased caffeine threshold in dilated cardiomyopathy would be a result of the enhanced resistance to the skinning procedure secondary to the modification of lipid species and/or content in sarcoplasmic reticulum membrane.

Heart valve replacement with the Sorin tilting-disc prosthesis. A 10-year experience

From 1978 to 1988, 697 patients with a mean age of 48 +/- 11 years (range 5 to 75 years) received a Sorin tilting-disc prosthesis; 358 had had aortic valve replacement, 247 mitral valve replacement, and 92 mitral and aortic valve replacement. Operative mortality rates were 7.8%, 11.3%, and 10.8%, respectively, in the three groups. Cumulative duration of follow-up is 1650 patient-years for aortic valve replacement (maximum follow-up 11.4 years), 963 patient-years for mitral valve replacement (maximum follow-up 9.9 years) and 328 patient-years for mitral and aortic valve replacement (maximum follow-up 9.4 years). Actuarial survival at 9 years is 72% +/- 4% after mitral valve replacement, 70% +/- 3% after aortic valve replacement, and 50% +/- 12% after mitral and aortic valve replacement, and actuarial freedom from valve-related deaths is 97% +/- 2% after mitral valve replacement, 92% +/- 2% after aortic valve replacement, and 62% +/- 15% after mitral and aortic valve replacement. Thromboembolic events occurred in 21 patients with aortic valve replacement (1.3% +/- 0.2%/pt-yr), in 12 with mitral valve replacement (1.2% +/- 0.3% pt-yr), and in seven with mitral and aortic valve replacement (2.1% +/- 0.8%), with one case of prosthetic thrombosis in each group; actuarial freedom from thromboembolism at 9 years is 92% +/- 3% after mitral valve replacement, 91% +/- 3% after aortic valve replacement, and 74% +/- 16% after mitral and aortic valve replacement. Anticoagulant-related hemorrhage was observed in 15 patients after aortic valve replacement (0.9% +/- 0.2%/pt-yr), in 9 after mitral valve replacement (0.9% +/- 0.3%/pt-yr), and in 6 with mitral and aortic valve replacement (0.9% +/- 0.5%/pt-yr); actuarial freedom from this complication at 9 years is 94% +/- 2% after aortic valve replacement, 91% +/- 4% after mitral valve replacement, and 68% +/- 16% after mitral and aortic valve replacement. Actuarial freedom from reoperation at 9 years is 97% +/- 2% after mitral and aortic valve replacement, 92% +/- 4% after mitral valve replacement, and 89% +/- 3% after aortic valve replacement, with no cases of mechanical fracture. The Sorin valve has shown a satisfactory long-term overall performance, comparable with other mechanical prostheses, and an excellent durability that renders it a reliable heart valve substitute for the mitral and aortic positions.

The risk of reoperation in patients with bioprosthetic valves

The risk of operative mortality in patients undergoing a first reoperation for bioprosthetic failure was assessed in a series of patients reoperated upon during the last two decades (1970-1990). A total of 330 such patients underwent replacement of 351 bioprostheses: 88 had aortic; 221 mitral; and 21 mitral and aortic bioprosthetic replacement. Indication for reoperation was in most cases structural valve deterioration (87%), followed by periprosthetic leak (7%) and endocarditis (6%). The operative mortality was significantly higher in patients who preoperatively were in New York Heart Association Functional Class IV or had a lower left ventricular function, in those reoperated because of prosthetic infection, and in those reoperated on an emergency basis. Structural valve deterioration was associated to a substantially low risk; operative mortality has improved in recent years, regardless of the indication for reoperation, partly due to the increasing experience and improved surgical techniques. Our results indicate that in recipients of bioprosthetic valves, careful follow-up with closer surveillance of valve and cardiac function and earlier prosthetic replacement might contribute to reducing the risk of reoperation.

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)

Influence of type of prosthesis on late results after combined mitral-aortic valve replacement

The influence of type of prosthesis on the late outcome of patients with combined mitral-aortic valve replacement was analyzed by comparing, at a 14-year follow-up, patients receiving two biological prostheses (group 1; n = 135), two mechanical prostheses (group 2; n = 221), or a mechanical prosthesis in the aortic position and a bioprosthesis in the mitral position (group 3; n = 97). No difference was found among the three groups in terms of actuarial survival and incidence of and freedom from valve-related deaths, thromboemboli, and hemorrhages. Patients with biological prostheses had a significantly greater incidence of structural valve deterioration, reoperations, and overall complications when compared with patients with only mechanical prostheses. The results of an extended follow-up of patients with combined mitral-aortic valve replacement indicate that mechanical prostheses perform better in the long-term owing to their superior durability when compared with biological valves. The use of bioprostheses should be confined to old patients with limited life expectancy because of their cardiac disease, provided that anticoagulants are not used. Combination of mechanical and biological prostheses in the same patient should be avoided because the advantages of each type of prosthesis are lost.

Failure of Hancock pericardial xenografts: is prophylactic bioprosthetic replacement justified?

The incidence of major valve-related complications was evaluated in a series of patients in whom the Hancock pericardial xenograft was used for aortic (AVR; n = 84), mitral (MVR; n = 17) and mitral-aortic (MAVR; n = 13) valve replacement. At 7 years actuarial survival is 66% +/- 8% after AVR, 64% +/- 13% after MVR, and 41% +/- 15% after MAVR, whereas actuarial freedom from valve-related death is 79% +/- 7% after AVR, 78% +/- 13% after MVR, and 81% +/- 12% after MAVR. Actuarial freedom from thromboemboli and anticoagulant-related hemorrhage at 7 years is 93% +/- 4% and 98% +/- 2% after AVR and 83% +/- 10% and 88% +/- 11% after MVR; no such complications occurred after MAVR. Structural valve deterioration determined at reoperation, at autopsy, or by clinical investigation was observed in 34 patients with AVR (10.0 +/- 0.2%/patient-year), in 10 with MVR (10.6 +/- 3.3%/patient-year), and in 9 with MAVR (16.6 +/- 5.5%/patient-year). After AVR, 19 patients underwent reoperation and 2 died before reoperation; 4 patients with MVR underwent reoperation, and 7 patients with MAVR underwent reoperation and 1 died before reoperation. Seventy-eight percent of the current survivors (13 patients with AVR, 7 with MVR, and 1 with MAVR) have clinical evidence of valve failure. At 7 years actuarial freedom from structural deterioration of the Hancock pericardial xenograft is 25% +/- 7% after AVR, 29% +/- 14% after MVR, and 0% after MAVR.(ABSTRACT TRUNCATED AT 250 WORDS)

Is lung biopsy useful for surgical decision making in congenital heart disease?

Sixty patients with congenital heart disease (CHD), age range 3 months-45 years (median 2 years), underwent lung biopsy to exclude pulmonary vascular disease (PVD): 25 had an atrioventricular (AV) septal defect, 14 a ventricular septal defect (VSD), 7 a complete transposition of the great arteries (TGA) + VSD, 3 an atrial septal defect, and 2 a patent ductus arteriosus; 9 had other malformations. Scoring of histological section (0-4) according to a modified Heath-Edwards classification disclosed that 30 patients had severe "irreversible" PVD (greater than or equal to grade 3) (11 AV septal defect, 8 VSD, 6 TGA + VSD and 5 others); 8 patients were younger than 1 year. Pulmonary vascular resistance (PVR) was calculated in 51 patients and exceeded 7 U/m2 in 1 of 2 patients with grade 0, in 9 of 18 with grade 1, in 1 of 4 with grade 2, in 11 of 18 with grade 3, and in 8 of 9 with grade 4. PVR was also calculated after 100% oxygen administration in 19 patients, 14 of whom had a resting PVR greater than or equal to 7 U/m2. PVR persisted greater than or equal to 7 U/m2 in 5 patients: 4 had PVD greater than or equal to grade 3 and died after surgery. PVR fell to under 7 U/m2 in 14 patients, 3 of whom had PVD greater than or equal to grade 3:1 patient with grade 4 was not operated upon and 2 with grade 3 were operated upon: all are alive. Follow-up in discharged living patients was 100%, with a mean of 50 months. Fifty-five patients underwent surgery with 10 early and 2 late deaths. Among the 12 subjects with a fatal outcome, 10 had irreversible lesions. The 5 non-operated patients all had irreversible lesions at biopsy, and are still alive.(ABSTRACT TRUNCATED AT 250 WORDS)

Constrictive epicarditis after open heart surgery: the turtle cage operation

A 60-year-old man developed constrictive epicarditis within 1 year after isolated mitral valve replacement (MVR). At reoperation, decortication of the thick epicardial layer resulted, impossible without a high risk of injury of the myocardium and major coronary arteries. Therefore, multiple longitudinal and transverse incisions were performed on the epicardial peel, which at the end acquired a turtle cage appearance allowing myocardial reexpansion, relief of constriction, and restoration of adequate hemodynamics.

The pathology of Hancock standard porcine valve prosthesis: a 20-year span of experience

A spectrum of events leading to tissue failure is responsible for late dysfunction of Hancock porcine valve xenografts: (a) Primary failure: dystrophic calcification, thrombosis, fibrous tissue overgrowth, primary tears, cuspal hematomas, and stent postbending. (b) Secondary failure: endocarditis and paravalvular leak. Dystrophic calcification is the main factor influencing long-term durability and accounts in our experience for 88% of primary failure, through different clinical presentations; particularly, incompetence by cusp tearing and egg-shell fragmentation is by far the most frequent mode of failure. Cusp degeneration by primary tears (in the absence of dystrophic calcification) is an uncommon event, due to lipid infiltration or to right coronary muscle shelf spontaneous or immuno-related disruption.

Influence of prosthetic design on durability of the Liotta porcine valve in the mitral position

From March 1979 to December 1984, the Liotta low-profile porcine bioprosthesis was employed for mitral valve replacement in 71 patients to avoid potential left ventricle-prosthesis mismatch occasionally observed with the standard, high-profile, Hancock porcine xenograft. Follow-up of 61 operative survivors showed at 10 years an actuarial survival of 67% +/- 7%, freedom from thromboemboli of 96% +/- 2%, freedom from structural deterioration of 63% +/- 11% and freedom from all Liotta bioprosthesis-related complications of 53% +/- 10%. Complications related to excessive protrusion of the stent into the left ventricular cavity were eliminated with the Liotta bioprosthesis; the peculiar stent configuration, however, was responsible for an increased rate of structural deterioration requiring reoperation in 10 patients (2.8% +/- 0.9%/patient-year) at a mean interval of 76 +/- 18 months after mitral valve replacement (range, 45 to 106 months). Common findings in all explants were cusp prolapse, cusp tears, and commissural rupture related to various degrees of tissue calcification, constantly leading to severe prosthetic incompetence. As also shown experimentally, such structural changes have been attributed to increased systolic stresses on the closed cusps, favored by excessive reduction of the stent height. Our experience shows that the Liotta bioprosthesis used for mitral valve replacement does not provide any clear-cut advantage over standard porcine bioprostheses and that its long-term durability appears affected by the unique prosthetic design.

Value of transesophageal echocardiography during repair of congenital heart defects

Two-dimensional transesophageal color Doppler echocardiography was employed intraoperatively in 30 children undergoing repair of a variety of simple and complex cardiac malformations. There were 16 female and 14 male patients, with a mean age of 9 +/- 3 years (range, 4 to 13 years) and a mean weight of 31 +/- 9 kg (range, 16 to 50 kg), 16 children weighing less than 30 kg. A standard, commercially available transesophageal echocardiography probe (5 MHz, 64 elements) was used in all patients without complications. Transesophageal echocardiography proved helpful in selecting the surgical approach, in assessing the adequacy of surgical repair, in detecting residual intracardiac shunts, and in allowing uninterrupted monitoring of ventricular performance throughout the procedure. Our initial experience suggests that transesophageal echocardiography is a valuable tool to be used in children with congenital cardiac malformations, particularly in those requiring complex intracardiac procedures. The amount of information obtained by the surgeon should favor the routine use of transesophageal echocardiography during open heart procedures and stimulate the development of probes to be safely used even in infants and newborns.

Right atrial myxoma originating from the inferior vena cava

A patient undergoing successful excision of a right atrial myxoma arising from the inferior vena cava is reported. The rarity of this case prompted a review of the literature in which only 2 other patients with a right atrial myxoma originating from inferior vena cava tissue were found.

Anomalies of the systemic venous return: a review

Congenital anomalies of the systemic venous connection to the heart represent a rather wide and heterogeneous group of malformations, whose physiological consequences may vary from nil to the most severe form of systemic arterial desaturation. The malformations may be summarized as follows: (1) Left superior vena cava connected to the coronary sinus, interrupted inferior vena cava and absent right superior vena cava that do not indicate surgical repair 'per se', but require some technical attention during open heart surgery performed for other anomalies; (2) Left superior vena cava connected to the left atrium, due to incorporation of the coronary sinus into the left atrial cavity, resulting in a right-to-left-shunt; (3) Right superior vena cava or inferior vena cava draining into the left atrium, both are extremely rare and require treatment for the ensuing right-to-left shunt; (4) Total anomalous systemic venous connection to the left atrium, usually combined with atrial isomerism and other very complex heart malformations; (5) Cor triatriatum dexter, which has been frequently diagnosed as an anomalous venous connection for its similar hemodynamic consequences. Such anomalies are reviewed with particular respect to their surgical implications.

Long-term performance of the Hancock porcine bioprosthesis in the tricuspid position. A review of forty-five patients with fourteen-year follow-up

Because little information is available regarding the clinical performance of the Hancock porcine bioprosthesis (Johnson & Johnson Cardiovascular, King of Prussia, Pa.) implanted in the tricuspid position, we reviewed the long-term follow-up of patients who had tricuspid valve replacement with this device. From March 1970 to December 1983, 45 patients had tricuspid valve replacement, either isolated (seven patients) or combined with replacement of other valves (38 patients) by means of a standard, glutaraldehyde-preserved Hancock porcine bioprosthesis. Follow-up ranged from 0.2 to 14.7 years (mean, 7.6 +/- 3.6 years) and was complete. The late mortality rate was 6.6% +/- 1.6%/pt-yr and the actuarial survival rate at 14 years was 23% +/- 9%. Reoperation because of structural deterioration of the tricuspid, the mitral, or both bioprostheses was performed in nine patients (3.7% +/- 1.2%/pt-yr) from 40 to 177 months (mean, 112 +/- 43 months) and resulted in no deaths. Actuarial freedom from structural deterioration of a Hancock tricuspid porcine bioprosthesis at 14 years is 68% +/- 13%. Morphologic examination of explanted porcine bioprostheses showed that those implanted in the tricuspid position had lower degrees of calcification and less severe structural changes than those simultaneously explanted from the mitral position. We conclude that the Hancock porcine bioprosthesis has an acceptable long-term durability and satisfactory performance after tricuspid valve replacement, and we continue to favor its use in the tricuspid position even in association with mechanical prostheses in the left side of the heart.

Outcome of 290 patients with aortic dissection. A 12-year multicentre experience

Retrospective data regarding 290 patients suffering from spontaneous aortic dissection between January 1976 and June 1987 are reported. Dissection was always documented by retrograde aortography and data were collected from 11 catheterization laboratories operating in North-East Italy. The results show that over a 12-year period there was an increase in cases, an increase in the number of operations and a decline in operative mortality. Multivariate discriminant analysis demonstrated that acute myocardial infarction, persistent shock and persistent central neurologic deficit were significant independent predictors of operative mortality in type A patients. Only persistent shock was significantly related to higher operative mortality in type B patients. Late deaths occurred in 14/118 operated patients, and were mostly secondary (directly or indirectly) to aortic dissection. Discharged patients underwent frequent medical checks and chronically received drugs to control hypertension and reduce inotropism. Most of them (73.7%) were asymptomatic: careful post-operative medical assistance is necessary to guarantee the long-term success of surgical treatment.

Surgical excision of intracardiac myxomas: a 20-year follow-up

Since November 1968, 54 patients have undergone excision of an intracardiac myxoma, which was located in the left atrium in 46 (85%), in the right atrium in 6 (11%), and in the right ventricle in 2 (4%). There were 35 female and 19 male patients with a mean age of 48 +/- 14 years (range, 7 to 68 years). Four patients were asymptomatic; the others were seen mostly with exertional dyspnea, palpitation, signs of systemic illness, and syncopal episodes. Before operation, embolic episodes occurred in 13 patients with a left atrial myxoma. There were two early (3.7%) and two late deaths (3.8). Actuarial survival at 20 years is 91% +/- 4%, and most of the current survivors are asymptomatic at a mean follow-up of 6.5 +/- 5 years (range, 0.2 year to 20 years). Noninvasive reevaluation was performed with echocardiographic studies in 44 patients and 24-hour electrocardiographic monitoring in 34. No instances of tumor recurrence were observed, and there was a low incidence of major supraventricular arrhythmias late postoperatively. We conclude that excision of intracardiac myxomas is curative and long-term survival is excellent. The transseptal approach provides adequate exposure and allows complete removal of the tumor regardless of its location.

Intracardiac metastatic melanoma: report of a case mimicking a right atrial myxoma, with a review of the literature

A 49-year-old patient, referred with a diagnosis of right atrial myxoma, was found at surgery to have extensive cardiac metastases from a previously undetected cutaneous melanoma. In reviewing the literature, we found 5 other patients with a clinical diagnosis of melanoma metastatic to the heart, all of whom had a previous history of melanoma. In no other case has cardiac involvement been the 1st manifestation of a malignant cutaneous melanoma.

Early and late survival of repaired type A aortic dissection

From 1 January 1977 to 31 December 1988, 119 patients were operated upon for type A aortic dissection. The maximum follow-up was 11.7 years (median 5.6 years); follow-up was 100% complete. Actuarial survival was 47.3% +/- 5%. The death risk decreased rapidly to a constant rate of 0.0027 events/month after 3 months. There were 41 early deaths, mostly due to haemorrhage, brain damage and low output syndrome. A significantly higher probability of early death was observed in patients with preoperative myocardial ischaemia or infarction (P less than 0.0001) or preoperative cerebral symptoms (P = 0.0002). Extended dissection increased the risk proportionally to the length of the aorta involved (P = 0.0002). Typical dissection originating from an intimal tear in the ascending aorta had a significantly lower operative risk than atypical dissection with an intimal tear not localized in the aortic root (P = 0.0006). Of the 14 late deaths, 2 were unrelated to dissection, 2 were of unknown origin and 4 were sudden. Stroke was the cause of 2 and congestive heart failure the cause of 4 deaths. The probability of late death was higher in patients with perioperative brain damage (P = 0.003) and in patients with preoperative shock (P = 0.0025). It was significantly lower in patients with dissection of hypertensive aetiology (P = 0.002). There were 13 reoperations on 12 patients. Early reoperations were due to rupture of the distal aortic anastomosis. Late reoperations were mostly due to dehiscence of aortic valvular prosthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary artery bypass with inverted internal mammary artery: angiographic evidence of late graft patency

The internal mammary artery (IMA) is currently considered as the graft of choice for myocardial revascularization procedures. We report on two patients who underwent successful coronary artery bypass surgery using retrograde IMA flow. We provide, for the first time, angiographic evidence of late patency of an inverted IMA graft.

Surgical pathology of aortic valve disease. A study based on 602 specimens

A consecutive series of 602 surgically excised aortic valves was evaluated by means of macroscopic and histological study. Pure aortic stenosis was diagnosed in 140 patients, pure incompetence in 254 and combined dysfunction in 208. Of the cases with pure aortic stenosis, 38% were rheumatic, 34% were calcified bicuspid valves and 23% showed dystrophic calcification. Half the patients with pure aortic regurgitation showed aortic root dilatation. Most cases of combined aortic stenosis and regurgitation were the sequelae of rheumatic fever. A male prevalence was detectable in each group (mean male: female ratio = 2.6), and was highest in infective endocarditis and aortic root dilatation. Infective endocarditis was a frequent complication of congenitally bicuspid valves. In conclusion, rheumatic disease is still a frequent cause for surgical replacement of the aortic valve. At least half the explanted aortic valves have degenerative or congenital diseases which are often the site of a superimposed infective endocarditis.

Heterotopic heart transplantation--a means to increase donor availability

From November 1985 to August 1989, 105 patients underwent heart transplantation at our institution of whom 8 (7%) underwent heterotopic heart transplantation (HHTx). There were 7 males and 1 female with a mean age of 49 +/- 6 years (range, 41-58 years), 7 of whom had ischaemic cardiomyopathy and 1 had dilated cardiomyopathy. The indications for HHTx were gross donor/recipient size mismatch, unreliable donor heart, elevated pulmonary vascular resistance and the need for urgent transplantation or their combination. HHTx was performed as a left ventricular bypass in 6 patients and as biventricular bypass in 2 combined with various surgical procedures on the native heart in 5. There was one perioperative death with a mean follow-up of the survivors of 17 +/- 10 months (range, 6-30 months). Comparison of preoperative and postoperative (1 year) 2-D echocardiographic studies of the native heart showed haemodynamic stability of the latter with no substantial changes in left ventricular ejection fraction and cardiac index, while left ventricular end-diastolic volume tended to increase in 2 patients. In conclusion, preservation of the native heart allows recovery or growth of a graft considered unsuitable for orthotopic transplantation. Our experience confirms that HHTx may still be considered a valuable alternative to orthotopic transplantation in selected patients, thus expanding donor utilization.

Late failure of double-inlet left ventricle septation: treatment by orthotopic heart transplantation

We report a patient in whom orthotopic heart transplantation was performed after late failure of ventricular septation for double-inlet left ventricle. This case shows that orthotopic heart transplantation represents a valid therapeutic alternative in children with previous correction of complex congenital heart defects not amenable to further intracardiac repair.

Aortic valve replacement with the Hancock standard, Björk-Shiley, and Lillehei-Kaster prostheses. A comparison based on follow-up from 1 to 15 years

Three series of patients undergoing isolated aortic valve replacement with the standard glutaraldehyde-preserved Hancock porcine bioprosthesis, the standard Björk-Shiley spherical disc prosthesis, and the Lillehei-Kaster tilting disc prosthesis were compared during a 15-year follow-up. From March 1970 to December 1985, aortic valve replacement was performed in 506 patients, 379 men and 109 women, whose ages ranged from 17 to 71 years (mean, 47 +/- 12 years); 196 had a Hancock bioprosthesis, 147 a Björk-Shiley prosthesis, and 163 a Lillehei-Kaster prosthesis. There were no significant differences among the three groups in terms of mean age, preoperative New York Heart Association class, valve lesion, associated intracardiac procedures, and operative mortality (11.7% for the Hancock bioprosthesis group, 8.8% for the Björk-Shiley prosthesis group, and 9.2% for the Lillehei-Kaster prosthesis group). Cumulative duration of follow-up is 1140 patient-years (mean, 6.6 +/- 1.5 years, 100% complete) for Hancock bioprosthesis patients, 878 patient-years (mean, 5.9 +/- 0.4 years, 98% complete) for Björk-Shiley prosthesis patients, and 1184 patient-years (mean, 7.3 +/- 0.3 years, 97% complete) for Lillehei-Kaster prosthesis patients. Actuarial survival rates at 15 years are 30% +/- 15% for Hancock bioprosthesis, 49% +/- 6% for Björk-Shiley prosthesis, and 44% +/- 7% for Lillehei-Kaster prosthesis patients. There were eight embolic episodes in Hancock valve recipients (0.7% +/- 0.1%/pt-yr), nine in Björk-Shiley prosthesis recipients (1.0% +/- 0.3%/pt-yr), and nine (0.7% +/- 0.1%/pt-yr) in Lillehei-Kaster prosthesis recipients (p = no significant difference). Actuarial freedom from emboli at 15 years is 89% +/- 4% for Hancock, 92% +/- 3% for Björk-Shiley, and 93% +/- 2% for Lillehei-Kaster prosthesis recipients (p = no significant difference). A significant difference was found in the incidence of the following complications. (1) Anticoagulant-related hemorrhage: 0.1% +/- 0.1%/pt-yr for Hancock bioprosthesis, 1.3% +/- 0.3%/pt-yr for Björk-Shiley prosthesis, and 1.9% +/- 0.4%/pt-yr for Lillehei-Kaster prosthesis patients (p less than 0.001), with an actuarial freedom at 15 years of 97.6% +/- 1% for Hancock, 85% +/- 5% for Björk-Shiley, and 68.8% +/- 10% for Lillehei-Kaster recipients (p less than 0.001). (2) Structural deterioration: 3.7% +/- 0.6%/pt-yr for Hancock and none for Björk-Shiley and Lillehei-Kaster patients (p less than 0.001), with an actuarial freedom of 100% for Björk-Shiley prosthesis and Lillehei-Kaster prosthesis patients and 38.4% +/- 12% for Hancock bioprosthesis patients at 15 years.

[Cardiac echinococcosis. Description of a case with cysts localized in the free wall of the left ventricle]

A case of isolated cardiac echinococcosis is reported. A 19-year-old man was hospitalized for chest pain with electrocardiographic pathological Q waves in D1, aVL, V5, V6. Two-dimensional echocardiography and chest computed tomography documented pericardial effusion and an intramyocardial cyst. Casoni's reaction and immunological tests completed the diagnosis of cardiac hydatidosis. The localization and the etiology of the cyst were confirmed during cardiac surgery.

The Hancock II porcine bioprosthesis. A preliminary report

From May 1983 to July 1987 a total of 153 Hancock II porcine bioprostheses have been implanted in 130 patients with a mean age of 59 +/- 8 years (range 29 to 76 years). Mitral valve replacement was performed in 72 patients, aortic valve replacement in 35, and mitral-aortic valve replacement in 23. Cumulative follow-up of 121 survivors is 223 patient-years and 100% complete (range 0.4 to 4.5 years). The actuarial survival rate at 4 years is 88% +/- 8% for mitral, 86% +/- 7.8% for aortic, and 84% +/- 8% for mitral-aortic valve replacement. Minor thomboembolism occurred in two patients (0.9% +/- 0.6%/pt-yr) with an actuarial freedom from emboli at 4 years of 100% for mitral, 96% +/- 3.7% for aortic, and 91% +/- 8.6% for mitral-aortic valve replacement. Anticoagulant-related hemorrhage occurred in 10 patients (4.4% +/- 1.4%/pt-yr) with an actuarial freedom at 4 years of 90% +/- 4.8% for mitral, 89% +/- 5.8% for aortic, and 84% +/- 10.6% for mitral-aortic valve replacement. Failure of the porcine bioprosthesis was observed in three patients with an actuarial freedom at 4 years of 96% +/- 3.6% for aortic, 91% +/- 8% for mitral, and 91% +/- 8.6% for mitral-aortic valve replacement. Actuarial freedom from all porcine bioprosthesis-related complications at 4 years is 85.7% +/- 6.6% for aortic, 79% +/- 9% for mitral, and 70% +/- 13% for mitral-aortic valve replacement. No instances of primary tissue failure occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Valve replacement in children: early and late results

In order to analyze the problems associated with prosthetic valve replacement (PVR) in the pediatric population, we have reviewed 29 children, 3.5 to 15 years of age, who were operated upon from 1970 to 1986. The indications were congenital valve malformations in 16 patients, rheumatic valve disease in 7, degenerative disease in 2 and bacterial endocarditis in 4. Ten children underwent aortic valve replacement (AVR), 14 mitral valve replacement (MVR), 1 tricuspid valve replacement and 4 double valve replacement (mitral-aortic in 3 and mitral-tricuspid in 1). Twenty-one mechanical (11 aortic and 10 mitral) and 12 biological prostheses (8 mitral, 2 aortic, and 2 tricuspid) were implanted. There was 1 hospital death (3.4%). Follow-up data were available for all survivors from 3 to 184 months. There were 8 late deaths (5.9% patient-year), 4 among children with mechanical and 4 among those with biological prostheses. Overall actuarial survival at 14 years is 62.5 +/- 10.2% with no significant difference in survival between AVR (77.8 +/- 14%) and MVR (44.4 +/- 16%) (p = 0.31) at 10 years and between recipients of mechanical (65.7 +/- 13%) or biological prostheses (60.0 +/- 15%) (p = 0.62) at 6 years. No documented embolic or anticoagulant-related complications occurred in the entire series.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical pathology of disease of the mitral valve, with special reference to lesions promoting valvar incompetence

A consecutive series of 459 mitral valves, which had been surgically excised over a 6-year period, were evaluated by means of macroscopic and histologic study. Of the valves, 379 specimens showed evidence of rheumatic disease (82.6%), 51 were floppy (11.1%), while 29 (6.3%) belonged to a heterogeneous group. The last included cases of ischemic disease (2.4%), infective endocarditis (2.4%), congenital dysplasia (0.9%), rheumatoid arthritis (0.4%), and primary dystrophic calcification (0.2%). Eighty-seven patients had had pure mitral incompetence. Among these, floppiness of the leaflets was the major indication for valvar replacement (58.6%), followed by rheumatic disease (12.7%), ischaemic incompetence (12.7%), and infective endocarditis (11.5%). Particular attention was paid to the clinical-pathological profile of patients with floppy valves as the cause of severe incompetence. This confirmed the prevalence of male patients and the frequent incidence of complications, particularly rupture of tendinous cords (54.9%). A striking difference was also found between the mean age of those patients with and without Marfan's disease (15.3 vs. 53.9 years, P less than 0.001). Although mitral incompetence in the presence of a floppy valve could simply be due to deformity of the leaflets, elongation of the cords and dilatation of the atrioventricular junction, in over half of the cases the precipitating event leading to surgery was rupture of tendinous cords.

Late results after resection of discrete and tunnel subaortic stenosis

From May 1969 to June 1988, 84 consecutive patients ranging in age from 6 months to 61 years (mean 18 years) underwent surgery for fixed subaortic stenosis (SAS). A discrete fibrous or fibromuscular structure was present in 81 patients, while 3 presented with a tunnel type of obstruction. SAS was treated by sharp resection of the tissue and routine myotomy or myectomy of the hypertrophied left ventricular (LV) muscle (57 patients, group 1), while more recently, the lesion was treated by simple fibrous tissue enucleation (27 cases, group 2). There were 3 hospital deaths (3.6%) and 3 late deaths (overall mortality 7.1%). Eight patients required late reoperation because of recurrent SAS [3], aortic valve stenosis [2], aortic incompetence (AI) [2] and persistent mitral incompetence [1]. Seventy of 78 late survivors were reevaluated 3 months to 110 months after surgery (mean 75 +/- 48 months) by means of a complete cardiac catheterization or by 2-D echo and Doppler. The transaortic peak pressure gradient decreased from 97 +/- 43 (range 20-205 mmHg) to 11 +/- 16 mmHg (range 0-60 mmHg) in group 1 and from 72 +/- 38 mmHg (range 18-160 mmHg) to 3 +/- 7 mmHg (range 0-25 mmHg) in group 2 (P = NS). In 55 patients who have not undergone surgery on the aortic valve, AI remained unchanged in 31, decreased from mild to nil in 21 and from moderate to mild in 3. We conclude that simple blunt enucleation of SAS is an effective procedure in relieving LV outflow obstruction even if a myotomy or myectomy of the underlying hypertrophied muscle is not routinely used.(ABSTRACT TRUNCATED AT 250 WORDS)

Repair of congenital malformations of the mitral valve in children: early and long-term results in 34 cases

From March 1972 through December 1986, 34 children underwent surgical treatment of mitral valve dysplasia at our institution. There were 14 males and 20 females, with a mean age of 6 years (range, 5 months to 15 years). Eighteen patients had significant mitral valve insufficiency; 16 had significant mitral valve stenosis. Mitral valve reconstruction was possible in 30 patients (88.2%); replacement of the mitral valve with a mechanical prosthesis was necessary in the other 4 patients (11.8%), after at least 1 attempted reconstruction. Five patients died in the hospital (14.7%): 4 after conservative surgery, and 1 after mitral valve replacement. A 6th patient died 26 months after mitral valve replacement and resection of a subaortic membrane. Four patients required reoperation 2 to 66 months after conservative treatment: in 3 of these, the mitral valve was replaced; in the 4th, additional reconstruction was successful. Upon follow-up (range, 3 months to 14 years after surgery), 26 of the 28 surviving patients were asymptomatic; 2-dimensional and Doppler echocardiography performed in 22 patients after mitral valve repair showed normal pulmonary artery pressure in all, and moderate mitral valve dysfunction in 2. Our results indicate that reconstructive surgery for mitral valve dysplasia may prove effective and reliable in children, despite the frequent severity of valve malformation. We believe, therefore, that mitral valve repair should always be attempted in the pediatric population to avoid the disadvantages of prosthetic valve replacement.

Mitral valve replacement with the Hancock, Björk-Shiley and Lillehei-Kaster prostheses. A comparison based on a 15-year follow-up

The performance of the standard Hancock porcine bioprosthesis (HPB), the Björk-Shiley spherical disc prosthesis (BSP) and the Lillehei-Kaster tilting disc prosthesis (LKP) was compared over a 15-year follow-up in patients who underwent isolated mitral valve replacement (502 HPB, 183 LKP and 119 BSP). The cumulative duration of follow-up is 3,488 patient-years (mean, 8.0 +/- 3.7 years) for patients with a HPB, 1,302 patient-years (mean, 8.4 +/- 4.9 years) for patients with a LKP and 718 patient-years (mean, 7.1 +/- 5.6 years) for those with a BSP. At 15 years a significant difference was found among the 3 groups in freedom from (1) anticoagulant-related haemorrhages, between HPB (83% +/- 7%) and BSP (65% +/- 8%) recipients (P less than 0.05); (2) prosthetic dysfunction, BSP (96% +/- 3%) and LKP (83% +/- 6%) versus HPB (42% +/- 5%) recipients (P less than 0.001); (3) overall reoperations, BSP (94% +/- 3%) and LKP (89% +/- 3%) versus HPB (40% +/- 5%) recipients (P less than 0.001) and (4) prosthetic failure, BSP (88% +/- 4%) and LKP (71% +/- 6%) versus HPB (38% +/- 5%) recipients (P less than 0.001). No difference was found in actuarial survival, freedom from thromboembolic episodes, treatment failure and overall prosthesis-related complications. Our results confirm that the long-term performance of the HPB in the mitral position is adversely affected by the high incidence of tissue degeneration while haemorrhagic complications may limit the advantage of the longer durability of mechanical prostheses.(ABSTRACT TRUNCATED AT 250 WORDS)

Technical considerations in reoperation for porcine bioprosthetic valve failure

Reoperation in porcine valve recipients is becoming increasingly frequent, owing to the limited durability of the valves. In reviewing our experience with first reoperation for porcine valve failure in 191 patients over a 17-year period, we found that following certain routine surgical steps can minimize complications and improve the surgical outcome. Extended dissection of the heart is useful during mitral bioprosthetic replacement to enhance visualization of the failing device while retracting the left atrium without undue tension on fragile structures such as the left innominate vein-superior vena cava junction. This maneuver can be avoided, however, when replacement of an aortic bioprosthesis is required. Excision of a porcine valve is performed by peeling off the fibrous tissue overgrown on the sewing ring, which exposes the underlying sutures, cutting each knot, and finding a plane between the stent and the native valve annulus by careful blunt dissection. Care is taken not to cut the Dacron cloth of the sewing ring to avoid the potential for embolization of the silicone sponge contained within it. The use of this technique helps to minimize postoperative complications such as paravalvular leak or atrioventricular block and to preserve the native annulus, which facilitates insertion of a new prosthesis. Our experience indicates that first reoperation in porcine valve recipients can be performed with low risk, particularly in elective cases, and with a low incidence of complications related to repeat median sternotomy.