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Background: In prospective randomized trials at 1 year, transmyocardial revascularization (TMR) provided superior relief of angina, decreased rehospitalizations, and improved exercise times. We evaluated 5-year mortality and angina class in "no-option" patients with diffuse coronary artery disease randomized to TMR or continued medical management., Methods: Two hundred twelve patients with refractory class IV angina who were not candidates for conventional therapy were randomized to receive holmium:yttrium-aluminum-garnet TMR (n = 100) or continued medical management (n = 112) at nine centers. Follow-up included all-cause mortality along with angina class assessment by blinded evaluators. Mean follow-up was 5.7 +/- 0.8 years., Results: Mean angina scores for TMR patients were 4.0 +/- 0.0 at baseline, 1.5 +/- 1.4 at 1 year, and 1.2 +/- 1.1 at a mean of 5 years (p < 0.001). After an average of 5 years, a significantly greater proportion of TMR than medical management patients experienced two or more class improvement in angina (88% versus 44%; p < 0.001). Kaplan-Meier intention-to-treat survival at 5 years was 65% versus 52% (TMR versus medical management; p = 0.05). Cumulative hazard curves demonstrated a significantly reduced risk of late death for TMR patients; average annual mortality beyond 1 year was 8% versus 13% (TMR versus medical management; p = 0.03)., Conclusions: Five-year follow-up of prospectively randomized, no-option class IV angina patients demonstrated significantly increased Kaplan-Meier survival in patients randomized to TMR. The significant angina relief observed 12 months after sole therapy TMR was sustained long term and continued to be superior to that observed for patients maintained on continued medical management alone.

Background: Transmyocardial revascularization involves the creation of channels in the myocardium with a laser to relieve angina. We compared the safety and efficacy of transmyocardial revascularization performed with a holmium laser with those of medical therapy in patients with refractory class IV angina (according to the criteria of the Canadian Cardiovascular Society)., Methods: In a prospective study conducted between March 1996 and July 1998 at 18 centers, 275 patients with medically refractory class IV angina and coronary disease that could not be treated with percutaneous or surgical revascularization were randomly assigned to receive transmyocardial revascularization followed by continued medical therapy (132 patients) or medical therapy alone (143 patients)., Results: After one year of follow-up, 76 percent of the patients who had undergone transmyocardial revascularization had improvement in angina (a reduction of two or more classes), as compared with 32 percent of the patients who received medical therapy alone (P<0.001). Kaplan-Meier survival estimates at one year (based on an intention-to-treat analysis) were similar for the patients assigned to undergo transmyocardial revascularization and those assigned to receive medical therapy alone (84 percent and 89 percent, respectively; P=0.23). At one year, the patients in the transmyocardial-revascularization group had a significantly higher rate of survival free of cardiac events (54 percent, vs. 31 percent in the medical-therapy group; P<0.001), a significantly higher rate of freedom from treatment failure (73 percent vs. 47 percent, P<0.001), and a significantly higher rate of freedom from cardiac-related rehospitalization (61 percent vs. 33 percent, P<0.001). Exercise tolerance and quality-of-life scores were also significantly higher in the transmyocardial-revascularization group than in the medical-therapy group (exercise tolerance, 5.0 MET [metabolic equivalent] vs. 3.9 MET; P=0.05); quality-of-life score, 21 vs. 12; P=0.003). However, there were no differences in myocardial perfusion between the two groups, as assessed by thallium scanning., Conclusions: Patients with refractory angina who underwent transmyocardial revascularization and received continued medical therapy, as compared with similar patients who received medical therapy alone, had a significantly better outcome with respect to improvement in angina, survival free of cardiac events, freedom from treatment failure, and freedom from cardiac-related rehospitalization.

The issue of bioprosthetic valve durability has become of critical importance as the number of elderly patients requiring valve operation has continued to increase. Our previous study showed bioprosthetic valve durability to be in excess of 83% at 13 years for patients 70 years of age and older at the time of implantation. There is limited follow-up data in the literature beyond this time point, however. Accordingly a retrospective analysis was conducted of all patients with bioprosthetic valves who were 70 years of age and over at the time of implantation. From September 1974 to April 1994, 1007 patients 70 years of age and over underwent valve replacement using a porcine bioprosthesis. The patients ranged in age from 70 to 104 years (mean, 75.6 +/- 4.3 years). There were 549 men (54.5%) and 458 women (45.5%). Preoperatively 98.8% of the patients were in New York Heart Association functional class III or IV. Operation was performed as an emergency in 66 patients (6.6%). The hospital mortality was 10.9% (110 patients), with 897 hospital survivors. There were 961 valves at risk. Follow-up extended from 1 month to 18.8 years (mean, 56.6 months). The cumulative follow-up is 4232.3 patient-years. A total of 31 valves failed, 12 in the aortic position and 19 in the mitral position (p < 0.0024). The causes of valve failure have included structural deterioration (16 valves), prosthetic endocarditis (7 valves), nonstructural dysfunction (5 valves), prosthetic thrombosis (1 valve), and other (2 valves).(ABSTRACT TRUNCATED AT 250 WORDS)

The number of patients undergoing valve replacement and concomitant coronary artery bypass grafting (CABG) is increasing. To further evaluate the indications for the use of the porcine bioprosthesis, this retrospective comparative analysis of valve structural deterioration was conducted in patients with and without concomitant CABG. From September 1974 to October 1993, 1,567 patients underwent valve replacement using a porcine xenograft. The series was divided into two groups: patients with isolated valve replacement (VR; n = 876) and those with VR and CABG (VR + CABG; n = 691). Aortic valve replacement was performed in 938 patients, mitral valve in 518, tricuspid in 2, and multiple valve replacement in 109 patients. The mean age for the series was 70.7 years (range, 50 to 104 years). The hospital mortality was 8.8% (138 patients). The hospital mortality for the VR group was 7.4% (65 deaths) and the VR + CABG group, 10.6% (73 deaths) p = 0.0365. There were 1,429 patients discharged from the hospital with 1,489 valves at risk. Follow-up extended from 1 month to 17.9 years with a mean of 66.9 months and was 98.3% complete. The cumulative follow-up was 7,927.1 patient-years. Structural deterioration was found to be significantly greater in the VR group for the age category 50 to 59 years (p = 0.0121) and the 60 to 69 years (p = 0.0230). No significant difference in the rate of structural deterioration was found for the two groups for the age category 70 years and older.(ABSTRACT TRUNCATED AT 250 WORDS)

The internal mammary artery has become the conduit of choice in myocardial revascularization. The expanded use of this ideal conduit for sequential grafting has enhanced its application. Between March 1985 and June 1993, 245 consecutive patients underwent revascularization of the myocardium with internal mammary artery bypass grafts with at least one sequential anastomosis. There were 186 men and 59 women, with a mean age of 65.1 (range 40-82) years. Unstable angina was present in 141 patients (57.6%) and 36 patients (14.7%) had left main coronary artery stenosis (> 50%). Before surgery, five patients (2.0%) were in New York Heart Association (NYHA) class II, 113 (46.1%) in class III, and 127 (51.8%) in class IV. There were a total of 1041 coronary artery grafts, mean 4.2 (range 2-7) grafts per patient and 528 sequential left internal mammary artery anastomoses, mean 2.2 per patient. Hospital mortality rate was 2.4% (six patients). Almost two-thirds of the patients experienced no hospital complications. The most frequent complication included arrhythmia in 36 patients (14.7%), respiratory insufficiency in 15 (6.1)% and temporary left phrenic nerve palsy in ten (4.1%). Mean follow-up was 37.0 (range 1-94.2) months. The mean(s.e.m.) actuarial survival rate for patients discharged from hospital was 94.8(1.6)% at 36 months and 82.4(5.0)% at 72 months. At follow-up of 222 patients, 185 (83.3%) were symptom-free in NYHA class I and 27(12.2%) were in class II. Though technically demanding, multiple sequential internal mammary artery grafting is feasible and can be accomplished with low hospital mortality and morbidity.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic valve replacement is the treatment of choice for elderly patients with aortic stenosis. It can be accomplished with excellent immediate and long-term results with significant functional improvement. Unfortunately, the literature is replete with enthusiastic reports of aortic catheter balloon valvotomy. Initial findings were controversial and the long-term results have been poor due to early valve restenosis. A retrospective analysis of our surgical experience with aortic valve replacement in the elderly seems appropriate in an effort to put this issue in proper perspective. From January 1973 to June 1993, 200 consecutive patients 70 years of age and older with severe aortic stenosis underwent surgical correction. There were 105 men (52.5%) and 95 women (47.5%), with a mean age of 76.2 years (range 70 to 89). Preoperatively, 195 patients (97.5%) were in New York Heart Association (NYHA) Class III or IV. Over one half (61.0%) of the patients experienced no hospital complications. The hospital mortality was 9.0% (18 patients). This included 14 patients in NYHA Class IV. The mean follow-up was 69.3 months and ranged from 1 to 215 months. The actuarial survival for 182 patients discharged from the hospital was 70.8% +/- 4.0% (SEM) at 72 months (73 patients at risk) and 35.2% +/- 5.4% at 144 months (20 patients at risk). Considering the advanced age and preoperative functional classification in this patient group, the results of aortic valve replacement have been excellent. The survival of patients discharged from the hospital compares favorably with a normal population matched for age and sex. The results of aortic balloon valvotomy have been disappointing.(ABSTRACT TRUNCATED AT 250 WORDS)

One hundred sixty-nine consecutive patients with coronary artery disease and mitral valve pathology operated during the past 5 years were reviewed (98% follow-up). Eighty-seven patients underwent mitral valve repair and 82 mitral valve replacement with concomitant coronary artery bypass grafting (number of AV grafts = 3). An analysis of these patients (age range 48 to 92 [mean 69]) and a classification based on anatomic pathology of the mitral apparatus is presented. Flexible ring annuloplasty was utilized in all repairs and chordal-sparing techniques in all valve replacements. There was equal mortality for replacement and repair in this subset of high risk patients. Structural valve dysfunction of repaired valves was more common (5/81 [6.0]) than primary tissue valve failure after mitral valve replacement (0 patients).

The expanded use of autografts for aortic valve replacement has focused attention on developing an improved implantation technique with the aim of reducing the incidence of early insufficiency. While the technique for total root replacement with nonstented tissue valves is a proven and established method, it is, however, not generally accepted for use in all clinical circumstances. Through the use of a partial inclusion technique, we propose to modify the standard method of extended aortic root replacement and pedicle coronary implantation. This approach also has the advantage of leaving the recipient aortic root intact. Unlike traditional scalloped subcoronary homograft implantation, it does not enclose the transplanted valve totally within the recipient aorta. Thus, there is preservation of the patient's aorta without distortion of the transplanted valve which occurs when it is forced completely into the closed recipient aortic root. While this partial inclusion method is not as simple as total root replacement, preservation of the recipient root is generally more acceptable to implanting surgeons. Either perfection of this proposed method or the acceptance of a traditional extended aortic root replacement will result in correction of the persistent problem of early aortic insufficiency following the use of autograft valves. Decreasing valve incompetence will have the desired effect of increasing the indication for the use of autografts for aortic valve replacement in young patients.

The problem of early onset aortic insufficiency as seen with the scalloped, subcoronary homograft aortic valve replacement is reduced with the use of a total root replacement. In addition, the naturally competent aortic root is more durable. From September 1985 to April 1991, 26 consecutive patients underwent aortic root replacement with 10 autografts, 14 homografts, and 2 xenografts using a modified implantation method. Twenty-five patients were discharged from the hospital. This partial inclusion root technique for implanting unstented valves in the aortic position decreases the probability of early failure secondary to technical malalignment at the time of implantation. In contrast to total root replacement, it avoids the need to destroy the recipient aortic root. A longitudinal aortotomy is performed to the aortic annulus in the mid-portion of the noncoronary sinus. The proximal suture line is interrupted with the valve oriented in the anatomical position. Circumferential running monofilament side-to-side anastomoses approximate the donor coronary ostia to the recipient. A running medial and lateral posterior suture line to the lateral superior portions of the aortotomy completes the integrity of the anterior wall of the implantation. One autograft attempt failed and one homograft patient died postoperatively. Follow-up ranges from 1 to 6 years in 24 patients. Postoperative aortic insufficiency was significant in one case due to inappropriate sizing of the proximal aortic suture line. There has been no evidence of progressive aortic insufficiency detected by the early onset of diastolic murmurs or echocardiograms as was our previous experience with the scalloped subcoronary method.

Since the advent of homograft aortic valve replacement surgery in the early 1960s, this procedure has been plagued by early aortic insufficiency. This problem has not been observed with total aortic root replacement. From September 1985 to April 1991, a modified method was used in 25 of 39 consecutive patients having aortic root replacement--seven having autografts, 30 having homografts, and two having xenografts. This technique is a new approach for implanting unstented valves in the aortic position. It decreases the probability of early failure resulting from technical malalignment of the valve during implantation. Further, it avoids the need to destroy the recipient aortic root. Whether the valve being used is an autograft, homograft, or xenograft, this method standardizes the insertion technique regardless of the anatomy or disease. Salient features of the method include the following: a longitudinal aortotomy to the aortic anulus in the midportion of the noncoronary sinus; a proximal interrupted suture line with the valve oriented in the anatomic position; and circumferential running monofilament side-to-side approximation of the donor coronary ostia to the recipient coronary ostia. The two anterior commissures are left untethered by nonclosure of the recipient aortotomy. Preliminary results have been impressive, with follow-up ranging from 1 to 3 years in 30 of these patients. Postoperative aortic insufficiency was significant in only two cases. There has been no progression of aortic insufficiency detectable by diastolic murmur or echocardiogram. Late complications have been minimal, and the overall clinical results have been excellent.

Since January 8, 1985, three different designs of unstented (type A, n = 9) and partial stented (type B, n = 4; and type C, n = 3) glutaraldehyde preserved porcine aortic valves were used for aortic valve replacement in 16 patients with acquired aortic valve lesions. Type A and type B prostheses were implanted using a two suture row technique. In type C prostheses, only a single suture row was necessary for implantation, facilitating surgery considerably. In all patients, the fully flexible commissures of the bioprostheses were secured to the aortic wall of the recipient. There was no hospital mortality. Two patients with type A bioprostheses died due to noncardiac causes, 4 and 24 months postoperatively. One bioprosthesis in this group had to be replaced after 3 months because of insufficiency. Serial Doppler echocardiographic studies were performed up to 6 years after implantation. No significant leaflet calcification was observed. In three type A bioprostheses, a mild insufficiency without progression was recorded. The latest mean/peak transprosthetic pressure gradients were: type A: 6 +/- 4 mmHg/12 +/- 6 mmHg; type B: 6 +/- 3 mmHg/14 +/- 5 mmHg; and type C: 11 +/- 5 mmHg/18 +/- 8 mmHg. The functional results of the type A and type B bioprostheses have proven to be satisfactory. The slightly higher pressure gradients in patients with a type C bioprosthesis give rise to further refinements of its design. These results confirm the usefulness of imitating normal anatomy by using unstented or partial stented bioprostheses.

With an increasing number of elderly patients requiring cardiac valve surgery, the topic of bioprosthetic durability becomes critically important. Previous reports have shown expected survival of bioprosthetic valves to be in excess of 95% at 9 years. However, primary tissue failure appears to accelerate at the end of the first decade and there is limited data into the second decade. With this in mind, we proceeded to analyze all bioprosthetic valves implanted in patients 70 years of age and older. From September 1974 to December 1990, 781 patients underwent valve replacement using a bioprosthesis. Ages ranged from 70 to 88 years with a mean of 75.1. There were 423 males (54.2%) and 358 females (45.8%). Preoperatively, 99.0% of the patients were in either New York Heart Association functional Class III or IV. Fifty-nine patients (7.6%) were done as emergencies. Six hundred ninety-four patients left the hospital (30-day overall mortality 11.1%). In this cohort, there were 733 valves at risk. Follow-up extended from 1 to 186.0 months with a mean of 52.9, which resulted in 3,059.9 patient-years of cumulative follow-up. Bioprosthetic Survival: A total of 23 valves failed in the series; 15 primary tissue failures, seven from endocarditis, and one perivalvular leak. Actuarial survival at 7 years was 94.5% +/- 1.4% standard error of the mean (SEM; 168 valves at risk) and at 13 years, 83.7% +/- 4.8% SEM (11 valves at risk). This analysis provides further documentation of the long-term favorable durability of the bioprosthesis when utilized in patients 70 years of age and over.

Stent mounting of homograft valves was first reported by our group in 1968. Since then, there has been question as to whether or not stent mounting of bioprostheses adversely affects the incidence of structural deterioration in aortic valve replacement. Between November 1967 and July 1988, 571 consecutive patients underwent valve replacement with a stented or unstented homograft. There were 351 men (61.5%) and 220 women (38.5%). The mean age of the group was 49.2 years (range 18 to 79 years). Five hundred thirty-four patients left the hospital (30-day overall mortality 6.5%). Follow-up extends from 6 months to 22 years with a mean of 7.6 years. The cumulative follow-up for the series was 4,095.9 patient-years. Hospital mortality, early technical failure, and prosthetic valve endocarditis were considered censoring events and excluded from this study. Actuarial analysis revealed a significant difference (p less than 0.02) in the freedom from structural valve deterioration for unstented and stended isolated aortic valve replacement. Age (50 and under, and over 50) does not appear to be a factor in structural deterioration in unstented homografts but does influence the rate of failure in stented homografts (p less than 0.05). These results clearly indicate that stent mounting adversely affects tissue valve durability with aortic valve replacement. Moreover, age correlates with structural deterioration if valves are stented and does not if they are unstented. Based on these results, the use of unstented bioprostheses should be reevaluated, along with the design of porcine valve stents.

Since September, 1985, 20 patients have undergone implantation of a homograft valve in the pulmonary position (16 pulmonary, 4 aortic). There were 11 primary operations and 9 reoperations. In 7 of 11 primary operations the homograft valve was utilized as a composite conduit with a short Dacron extension. In four of five reoperations for a failed porcine valved conduit, a composite homograft conduit was used. Four patients underwent implantation of a free homograft in a previously repaired right ventricular outflow tract (RVOT). Age ranged from 15 days to 22 years. There was one operative death (5%), a seven-week-old infant with truncus arteriosus. Long-term follow-up ranges from 1 to 30 months. Clinical performance has been satisfactory in 18 of 19 patients. One patient undergoing free implantation of a pulmonary valve in the RVOT required replacement at 18 months with a porcine valve. In this patient, pulmonary insufficiency was caused by distortion of the annulus secondary to dilatation and pulmonary hypertension. Nine of 18 survivors do not require medication. Eleven of 18 have trivial to mild pulmonary insufficiency murmurs without symptomatology. The homograft valve is extremely useful in reconstruction of the right heart, however, early insufficiency murmurs have been noted. Distortion of the valve annulus may contribute to the early onset of a benign insufficiency murmur. Residual distal obstruction or pulmonary hypertension may be a contraindication to the use of a free homograft in the orthotopic position.

Three hundred fifty-two patients underwent aortic (AVR) or mitral (MVR) valve replacement with a glutaraldehyde-preserved porcine xenograft from 1970 to 1980. Analysis of this series revealed the following information: hospital mortality, 11.6% (41/352); late mortality, 5.5% per patient-year (60/1,090.7); actuarial 5 year survival rate, 70%; incidence of thromboembolism and hemorrhage, 1.4% per patient-year (15/1,090.7); incidence of spontaneous degeneration, 1.1% per patient-year (12/1,090.7); and transvalvular gradient. AVR 16 mm Hg and MVR 4.6 mm Hg. These results compare favorably with results from other porcine xenograft series and with those reported for prosthetic valves. There is no apparent difference in the type of xenograft used with the exception that spontaneous degeneration occurred less frequently in mitral valves that had not undergone pressure fixation than in those that had. The use of flexible stents improved the ease of valve implantation but did not affect leaflet durability as anticipated. Calcification occurred randomly with no relationship to time of implantation. Reoperation was for spontaneous valve deterioration by calcification or collagen degeneration in 11 cases, paravalvular leak in 13 cases, and implantation of an undersized valve in four cases; there was one reoperation for infection. Results support the continued use of porcine xenografts and suggest that improved manufacturing techniques will reduce the incidence of spontaneous, sterile deterioration, which is the only serious drawback to routine use of the porcine xenograft.

The incidence of perioperative myocardial infarction (MI) and acute ischemic injury was determined in 44 patients having aortic valve replacement plus aortocoronary vein grafts (AVR + CABG) and in 22 patients having mitral valve repair or replacement plus aortocoronary vein grafts (MVR + CABG). These data were correlated with aortic cross-clamp time, fibrillation time, presence of left ventricular hypertrophy, and, in selected cases, left ventricular biopsy. Perioperative MI occurred in 21% (9/44) of the AVR + CABG patients and 5% (1/22) of MVR + CABG patients. In contrast, the MI rate for isolated valve replacement was 7% (15/213), and for isolated CABG 14% (16/112). In the AVR + CABG group, 100% (5/5) of patients with combined cross-clamp and fibrillation times greater than 120 minutes suffered MI. These results indicate that patients with combined AVR + CABG are subject to substantially greater risk of perioperative myocardial damage than the other groups. Excessive aortic cross-clamp times and fibrillation plus aortic cross-clamp times should be avoided in AVR + CABG patients.

The advantages of a bloodless field and total cardiac relaxation have popularized the technique of deep hypothermia and total circulatory arrest for the correction of complex congenital cardiac defects in infancy. There is, however, a significant potential for cerebral and pulmonary complications. Presently, the most common technique is that of using a combination of surface cooling and cardiopulmonary bypass cooling and rewarming. Normal neurological development has been claimed with the present technique of hypothermia at 20 degrees C and total circulatory arrest for periods up to an hour; however, there are reports of seizure activity in the early postoperative period. There is also a disturbing incidence of respiratory insufficiency and, occasionally, hemorrhagic pulmonary edema. This study, using growing puppies and subjecting them to deep hypothermia and total circulatory arrest for varying periods of time, disclosed that animals subjected to 60 min of circulatory arrest recovered neurologically; however, there were histological changes of anoxia in the brain. Animals subjected to 30 min of total circulatory arrest were normal neurologically and there was no histological evidence of anoxic damage to brain tissue. Puppies that were continuously on cardiopulmonary bypass had no significant pulmonary changes caused by increasing the inspired oxygen tension in the ventilator; however, striking changes were noted when limited cardiopulmonary bypass was employed for core cooling and total circulatory arrest combined with pulmonary ventilation with 100% oxygen. We conclude from this experimental study that the use of surface cooling and core cooling with subsequent total circulatory arrest at 20 degrees C is a safe procedure, providing the period of time of cardiac arrest is kept around 30 min. We also conclude that the alveolar oxygen tension should be maintained at the lowest level possible during the interval of circulatory arrest to avoid the apparent rapid onset of post-traumatic pulmonary insufficiency.

The intravascular injection of contrast medium produces a rise of ventricular filling pressure which may reflect blood volume expansion, a negative inotropic effect on the myocardium, and/or a decrease in ventricular diastolic compliance. This phenomenon was studied by randomly infusing three substances, Renografin-76, 1% saline and 38% sucrose, into the aortic root of the isolated perfused canine heart. The preparation was modified by having an inflated ballon within the left ventricular cavity so that the end diastolic ventricular volume and afterload were fixed. A dose-related depression of left ventricular systolic pressure and peak dP/dt due to contrast media occurred, without a significant change in the left ventricular diastolic pressure. This decrease in ventricular contractility due to Renografin-76 could not be attributed entirely to either a saline or an osmotic effect. No significant changes were observed in left ventricular diastolic compliance. Sucrose was found to exhibit a marked positive inotropic effect.

To date, the glutaraldehyde porcine aortic valve xenograft has proved a good choice for valve replacement in both the aortic and mitral positions. Late thromboembolisms in the absence of long-term anticoagulation is virtually nonexistent in aortic valve replacement and very low in mitral valve replacement patients without a predisposing history. The hemodynamic performance of the porcine xenograft is adequate and comparable to that of mechanical prostheses. The potential for improved hydrodynamic function, particularly of very small sized valves, is great and already being realized. In spite of over 8 yr of xenograft experience, long-term durability remains the primary concern. Histologic study suggests that these valves undergo progressive postimplantation morphological alteration. However, to date, the incidence of tissue failure is very low. Although detailed reports of long-term valve series are surprisingly few, at present, there is no valve replacement device with a 10-yr experience proven structural integrity and a negligible incidence of valve-related morbidity. It will be 3-4 yr before a significant number of porcine xenograft patients either reach this point or experience valve failure. While this review of the valve literature does not permit a statistical comparison of valve types, we feel that it does allow us to attempt a general projection. On the basis of combined survival and valve-related complication rates, at 4 yr, the porcine xenograft appears to be a better choice than the mechanical prosthesis. Excessive tissue failure during the next 3-4 yr might reverse this opinion. However, even if an increase in valve failure does occur, the advantage of noncatastrophic disfunction and decreased valve-related complications may balance the risk of reoperative morbidity and mortality and continue to favor the porcine exnograft. Thus we could speculate that: (1) The tissue valve would be the valve of choice if (A) durability of 10 yr or more is proven, and valve complications with the xenograft remain as presently reported; (B) the incidence of valve complications with the mechanical prostheses at 10-yr follow-up continues to increase. (2) Mechanical prostheses would be the valves of choice if (A) xenograft valve failure is greater than 20% at 10 yr of follow-up; (B) the incidence of valve complications with the mechanical prostheses remains unchanged. (3) The choice of xenograft versus mechanical prosthesis will remain an open issue if valve failure and related complications with both types of device remain below 20% at 10-yr follow-up...

This study compares a retrospective consecutive series of human allografts and concurrent porcine xenografts implanted over a 10-year interval. There were 571 allograft valves and 1,351 xenograft valves implanted in the aortic and mitral position with mean follow-up of 12.8 years for the allografts and 6.2 years for the xenografts. This study compares the incidence of structural deterioration over long-term follow-up. We found that there was no significant difference between four manufacturers of porcine xenografts, in spite of substantial differences in processing techniques. We found that there was a significant difference in allografts that were premounted on stents as compared with allografts that were not premounted on stents for aortic valve replacement. We found that there was no significant difference between allografts for aortic valve replacement that were not premounted on stents and porcine xenografts implanted in the aortic position. These findings are in marked contrast to those of other reported series with the use of allograft valves.

After considerable experience, controversy persists between the selection of a tissue or prosthetic valve. In order to provide a nonbiased comparison, we designed a prospective, randomized study in September of 1970. Ninety-nine consecutive patients with isolated primary single valve replacement were randomized to tissue or prosthetic valves. The Tissue Bank supplied homografts which were either mounted for mitral replacement or used as free grafts for patients with small aortic roots. Starr-Edwards clot-covered prostheses were used for comparison. There was an even distribution of patients by age, sex, valve lesion, and New York Heart Classification attesting to the accuracy of the random selection. Anticoagulants were used in 33 patients who had operative or embolic evidence of atrial cloth or else history of thromboembolism. Thirty-five patients have undergone postoperative catheterization. Causes of death and valve failure are presented on an actuarial basis. Death in the Starr-Edwards patient group was sudden or due to fabric wear with subsequent thromboembolism, hemorrhage, or infection. We conclude that the tissue valve is a better choice for valve replacement. While there is no significant functional or hemodynamic apparent difference between the tissue and prosthetic valve, there is improvement in patient morbidity and mortality rate with the use of homografts, particularly in the aortic position. The primary cause of complications in the homograft is tissue deterioration, and this problem has been markedly reduced with advent of glutaraldehyde fixation. No such advance in solving the problem of host incompatability with the prosthesis has been forthcoming.

The Hancock II bioprosthesis was developed in order to provide the advantageous low pressure fixation, improved delrin stent design, and anticalcification treatment. These changes were made 6 years ago after 10 years of experience with the high pressure fixed rigid implantation ring and polypropylene stent used in the Hancock I valve. In 1983, based on our own experience with low pressure fixed valves in 76 patients, we began early clinical trials with the Hancock II valve. All valves were studied postoperatively by intraoperative catheterization and followed up with postoperative echocardiograms for measurement of valve gradients and areas. This series of 104 patients with Hancock II valves was then compared retrospectively with 119 patients receiving Hancock I valves from 1975 to 1983. A comparison of mortality, thromboembolism, and hemorrhage rates was not significantly different between groups and the valve failure incidence of Hancock I valves was an anticipated 2.34% per patient-year. There has been one primary tissue failure in the Hancock II series. This patient had fibrinous excrescences on the outflow surface of the valve in the aortic position. These nodules were compatible with an old thrombotic process of ill-defined nature. Further investigation resulted in reports of this phenomenon, which had resulted in early valve stenosis, from other centers implanting the Hancock II valve. In conclusion, the Hancock II bioprosthesis has theoretical advantages over the Hancock I in stent design, fixation pressure, and anticalcification potential. There is an unusual thrombotic process in aortic valve replacements that we have not observed in the Hancock I group or in our experience with other porcine xenografts.(ABSTRACT TRUNCATED AT 250 WORDS)

Of 581 aortic allografts implanted since 1967, 421 were analyzed for structural deterioration. This series is unique in that it includes patients from the early allograft experience. All allografts were cleanly procured, antibiotic sterilized, and either stored at 4 degrees C for up to 8 weeks or frozen to liquid nitrogen temperatures with cryopreservation to preserve the viable cusp fibroblasts. There were 25 frozen mounted aortic valves with a median time to valve failure of 12.1 years, which was not significantly different from the 12.5-year period for 114 fresh free-sewn aortic valves. The median time to valve failure was 6.6 years for 90 fresh-mounted aortic valves and 8.6 years for 192 fresh-mounted mitral valves (p = 0.05). The difference between all mounted and unmounted grafts was significant (p = 0.0001). In all groups, viable fibroblasts were present in specimens explanted up to 5 years after the operation. All specimens returned after more than 10 years were almost totally acellular. Evidence of increased collagen, suggesting that the fibroblasts survive implantation and then gradually die, was present in all specimens. This series suggests that durability of the unmounted viable allograft for aortic valve replacement is greater than for other types of tissue valves. Pre-mounted allografts for aortic or mitral valve replacement have a median survival of 8 years and are not more durable than other tissue valves.

A patient with bacterial endocarditis and no previous history of angina substained an acute anterolateral myocardial infarction while awaiting surgery. Selective coronary arteriography revealed a filling defect in the left anterior descending coronary artery with limited flow beyond the area of occlusion. A calcific embolus from the infected aortic valve was removed at the time of valve replacement, and the patient had an uneventful immediate postoperative course. Late postoperatively paravalvular aortic regurgitation recurred before and after a second repair.

Controversy persists as regards the efficacy of aortocoronary saphenous vein bypass graft (SVBG) compared to direct internal mammary artery (IMA) anastomosis. In general, the IMA graft (IMAG) is considered to be superior as regards postoperative patency. To avoid preselection bias, 74 consecutive, unselected patients with bypassable lesions of the left anterior descending artery (LAD) were randomized to undergo either SVBG or IMAG to the LAD in 1972-1974. The majority of patients had, in addition, SVBGs to other vessels. Postoperative angiograms, an average of 6 months after surgery, were obtained in two-thirds of the patients. The following observations were made: (formula: see text). In this series there is no clear advantage of the IMAG over the SVBG. The preparation of the internal mammary artery for grafting is tedious and the anastomosis more difficult to perform. The resultant flow in the internal mammary artery graft is less overall than in the SVBG. In over 400 unselected SVBGs to the LAD that have been restudied thus far in our practice, an 86% patency rate has been achieved.

Medical versus surgical treatment of unstable angina was compared in a prospective nonrandomized study of 118 patients. Acute transient ST-T wave changes were present during chest pain in all patients. Acute infarction was excluded by serial electrocardiograms and enzyme studies. All patients admitted to the coronary care unit from 1970 to 1975 who fulfilled the entry criteria were included in the study. The starting point for data evaluation was 5 days after hospital admission. Characteristics at entry were similar in 66 medically treated patients and 52 patients who had coronary bypass vein graft surgery. During a mean follow-up period of 23 months in 66 medically treated patients with unstable angina the incidence rate of nonfatal myocardial infarction was 17% and the total mortality rate 21 percent compared with respective rates of 19% and 5.8% in 52 surgically treated patients. In the surgical group 8 patients (15%) had a perioperative infarction and only 2 (4%) had a late infarction; one patient (2%) died at operation. Symptomatic improvement was observed more frequently in the surgically treated group. Sixty percent of surgically treated patients were free of angina compared with 21% of medically treated patients. Eight medically treated patients (12%) required late surgical treatment for persistent severe angina despite optimal medical management.

Six patients with tetralogy of Fallot, pulmonary atresia, or absent pulmonary valve syndrome were operated with a RVOT patch containing a single aortic allograft cusp from an adult donor. The method was based on animal work with similar patches implanted in growing puppies and proved that the single cusp functioned as an effective RV outflow valve for several weeks after surgery. Postoperative angiograms in the animals confirmed nearly completely competent valves. Sacrifice of animals at 3 months documented that the allograft tissue was flexible without early deterioration or calcification. Clinical application of this method raised several questions regarding the procedure, its efficacy, and subsequent fate of the allograft valve in children requiring RVOT reconstruction. There were six children age 19 months to 10 years who required division of the pulmonary valve annulus to relieve pulmonary outflow obstruction or with absent pulmonary valve syndrome and compromised airways from pulmonary insufficiency. One patient had a positive culture from the valve and required immediate removal of the infected allograft. Patients had clinically competent pulmonary valves immediately after surgery with decreased right ventricular systolic and end-diastolic pressures when compared with patients in whom nonvalve patches were inserted. All patients had some degree of pulmonary insufficiency, but no symptoms. Follow-up up of five patients available 4 to 6 years after surgery revealed no patients with stenosis of the valve cusps, although two patients have severe, one moderate, and two mild pulmonary insufficiency. We conclude that a patch containing a single adult allograft valve cusp should be considered for all patients requiring reconstruction of the RVOT, particularly if RV overload is expected to compromise the immediate postoperative result.

Sixteen patients with complex cyanotic congenital heart disease underwent an operation involving the use of the aorta and the main pulmonary artery as the egress for systemic arterial blood flow (the Damus-Kaye-Stansell operation, modified as discussed). The indication for this approach was either preoperative aortic outlet obstruction or likelihood that the repair would produce such obstruction. A modification of the original technique is introduced that involves transection of both great arteries, anastomosis of the contiguous aortic and pulmonic walls, and connection of the distal aorta to the perimeter of the new (bivalved) great artery. Eleven of the 16 patients survived operation: six of six who underwent a concurrent Fontan operation, four of six who underwent a concurrent right-ventricle-to-pulmonary-artery-conduit procedure, and one of four who underwent a concurrent systemic-pulmonary shunt procedure. Postoperative status in the 11 survivors is good: one patient has a gradient from the left ventricle to the aorta, 10 of 11 have little or no aortic regurgitation, and the remaining patients have a normal physiological status. We conclude that the Damus procedure is a useful addition to the surgical armamentarium for treatment of certain types of cyanotic congenital heart disease.

The incidence of myocardial infarction, acute ischemic injury, and associated serum enzyme abnormalities has been evaluated in four operations involving the coronary circulation. The highest incidence of infarction was associated with internal mammary implantation (Vineberg procedure). There was no significant difference in the incidence of infarction, ischemic injury, or abnormal enzyme levels between patients with stable angina and those with unstable angina who had vein bypass surgery. In operations involving combined vein bypass grafting and valve replacement surgery, the incidence of abnormal serum enzyme elevations was higher than in any other procedure. The incidence of infarction and acute ischemic injury in combined operations was similar to that in other procedures but this may have been due to the difficulty in the ECG diagnosis of infarction in this group of patients, most of whom had abnormal preoperative ECGs.

Coronary artery spasm was induced by intravascular administration of ergonovine maleate (Ergotrate) during cardiac catheterization. In 78 patients suspected to have Prinzmetal's angina, no morbidity or death has resulted despite complete occlusive spasm in two and three coronary arteries. Typical EKG changes and akinesia of the myocardium in the distribution of the occluded vessels documented functional myocardial ischemia during spasm. The occlusive spasm is readily reversed by sublingual or intravascular nitroglycerin, and ventricular contractility returns to normal following relief of spasm. Occlusive spasm has been demonstrated in 15 patients with clinical evidence of Prinzmetal's angina. Symptoms have been effectively relieved by coronary vasodilators in 10 patients. Of the 5 patients in whom medical therapy failed, 4 were treated surgically. These 4 patients were in the intensive care unit with protracted, prolonged pain, subendocardial infarctions, and persistent failure of coronary vasodilators. Aorta-coronary bypass grafts have been combined with total cardiac denervation by autotransplantation (one patient) and total cardiac denervation by stripping of the great vessels (3 patients). Two of the patients treated by cardiac denervation died in the early postoperative period. The patient treated by autotransplantation has total relief of symptoms but persistent spasm on angiography. The angiographic demonstration of occlusive coronary spasm remains a valuable diagnostic tool to document definitively the presence of spasm. The surgical results question the value of surgical intervention in this disease.

The factors that make mitral reconstruction an attractive alternative to valve replacement are increased anatomical valve orifice, preservation of the valvular apparatus, improved longevity over porcine xenografts, and no requirement for long-term anticoagulation. In our experience the majority of patients with mitral regurgitation have degenerative valve disease. This comparative series of patients operated on over a 10 year interval includes 72 with replacement and 112 with reconstruction. The average cross-clamp times were 69 minutes for reconstruction and 44 minutes for replacement. The hospital mortalities were 3.6% and 18.1%, respectively. Postoperative valve areas as determined by Doppler echocardiography were 2.69 cm2 for replacement and 2.67 cm2 for reconstruction (p = 0.9). The valve failure rate was 2.0% per patient-year for reconstruction and there were no failures in the replacement group. The reoperation incidence for reconstruction was 20% at 10 years. The remaining patients, although clinically well, had varying degrees of stable, nonprogressive mitral regurgitation. Forty-five percent had mild to trivial regurgitation detectable by echocardiographic studies. The decision between mitral valve reconstruction and mitral valve replacement remains a highly controversial issue. The failure of our data to demonstrate superior valve function for patients with mitral regurgitation undergoing valve reconstruction suggests a need for careful analysis of reconstruction with respect to effective valve orifice and incidence of regurgitation.

There is currently a renewed interest in the use of both fresh and commercially available frozen homograft valves for children and young adults. This has prompted us to review a series of 32 patients who received frozen homograft valves for aortic replacement between 1973 and 1975. The cryogenic technique evolved to include the use of selected antibiotics and equilibrated dimethyl sulfoxide solution to freeze homografts at a rate of 1 degrees C per minute to liquid nitrogen temperatures of -196 degrees C. Histologic sections of experimental frozen valves explanted 6 months postoperatively revealed the presence of viable donor cells, and tissue culture demonstrated the reproductive capacity of cusp fibroblasts. Of the 32 frozen viable homografts implanted in this series, 23 were inserted as free-sewn aortic replacements and nine were premounted on stents before implantation in the aortic position. There were two operative deaths, and three valves failed as a result of the technical problems of mounting in one patient and surgical insertion of a free graft in two patients. Of the 22 patients who remained at long-term risk, 13% with free-sewn grafts and 57% with premounted valves underwent reoperation for valve failure. After 10 years of follow-up, 15 (68%) of these patients, 12 (80%) with free-sewn and three (43%) with premounted valves, are alive with their original valve in place. Actuarial analysis shows that 58% of the 32 valves implanted are functional at the beginning of the eleventh year. There have been six late deaths resulting in an overall actuarial patient survival rate of 79% at 10 years and 69% after 13 years. These clinical results are believed to add support to our current application of the frozen homograft in selected patients.

A 4-year clinical experience with fresh allograft tissue valves prompted a trial of 0.5% buffered glutaraldehyde as a valve fixative and sterilant. Tanned allograft and porcine xenograft valves were inserted into experimental animals, and, beginning in 1970, similar valves were implanted in a series of patients now totaling 312. The clinical results are excellent. The 5-year valve-related mortality is 6% for patients who had mitral valve replacement and 16% for those with aortic valve replacement. To date, the incidence of thromboembolism is 1.3% per patient-year, and valve-related morbidity and mortality for the combined groups is 27.4%. Valve stent design has evolved from symmetrically configured metal to anatomically molded plastic. The maintenance of natural valve configuration has optimized leaflet coaptation and support, decreased tissue stress, and eliminated valve-stent dehiscence and tissue rupture seen in valves deformed to fit symmetrical stents. Stent design, controlled glutaraldehyde solutions, and fixation techniques have improved leaflet flexibility and reduced valve orifice to annulus diameter ratios, thus producing transvalvular gradients comparable to both mechanical and modified orifice tissue valves. To date, tissue failure, observed in only 1.0% (3 of 287) of patients, is the result of calcification (2 patients) and cusp rupture due to incomplete fixation (1 patient).