Valve replacement in the small aortic annulus: prospective randomized trial of St. Jude with Medtronic Hall.

OBJECTIVE: The ideal prosthesis for aortic valve replacement in patients with small annuli remains controversial and has yet to be identified. The purpose of this report is to compare the St. Jude (SJ) Medical and Medtronic Hall (MH) valves for aortic valve replacement in the small aortic root. METHODS: From 1986 to 1994 we prospectively randomized 456 patients to receive either the SJ or the MH valve. From this population, 80 patients (SJ, 42 patients; MH 38 patients) had a 19 or 21 mm aortic prosthesis inserted without annulus enlarging procedure. RESULTS: Follow-up was complete in all 80 patients for 270 patient years (mean 40.5 months). Analysis showed that the SJ and MH groups were similar with respect to age, gender, body surface area, valve area, NYHA class, ventricular function, prosthesis size, frequency of revascularization, bypass and global ischemic time. There were two operative deaths (1 SJ, 1 MH). Clinical performance and Dobutamine stress transesophageal doppler echocardiography could not demonstrate a significant advantage of one prosthesis over the other in this population. The change in aortic valve gradient, and left ventricular mass index measured preoperatively and within 12 months postoperatively were not different in both cohorts. CONCLUSION: The study could not detect a difference in the performance of the SJ and MH heart valves for aortic valve replacement in patients with small aortic annuli.

Management of asymptomatic mild aortic stenosis during coronary artery operations.

BACKGROUND: Management of asymptomatic mild aortic stenosis at the time of coronary artery bypass grafting (CABG) remains controversial. We have retrospectively analyzed a cohort of patients requiring aortic valve replacement (AVR) subsequent to CABG and compared their operative morbidity and mortality with that of a group receiving CABG and AVR simultaneously at the first operation. METHODS: Analysis is drawn from 28 patients who required AVR 8 +/- 4 years subsequent to CABG (group A) and 175 patients receiving AVR along with CABG at the primary operation (group B). Groups were similar with respect to age, sex, risk factors for cardiac disease, extent of coronary artery disease, left ventricular function, New York Heart Association class, aortic valve area, number of grafts, and size of prosthesis inserted. RESULTS: Patients having AVR subsequent to CABG had a significantly prolonged aortic cross-clamp time and global myocardial ischemic time and incurred a twofold increase in operative mortality. The actuarial survival at 10 years was not significantly different between cohorts. In the 28 patients in group A, the aortic valve area during the period between operations decreased 0.05 mm2/y. CONCLUSIONS: The operative mortality and morbidity of a second operation for AVR is high, but there is no significant difference in survival at 10 years. In at least a portion of patients having mild aortic stenosis at the time of CABG there will be progression of the stenosis necessitating reoperation at a later date.

Effect of advancing age on cost and outcome of coronary artery bypass grafting.

The clinical and billing records of 250 patients (173 men and 77 women) undergoing isolated coronary artery bypass grafting between 1987 and mid-1990 were retrospectively reviewed to determine charges and clinical results as related to age. Patients were stratified by age into five groups of 50 consecutive patients each: group 1, less than 50 years of age; group 2, 50 to 59 years; group 3, 60 to 69 years; group 4, 70 to 79 years; and group 5, 80 years or older. The groups were compared in regard to perioperative clinical variables, long-term follow-up, and total charges. Group 5 had significantly more postoperative complications than the other four groups (p < 0.05). In addition, length of postoperative hospitalization was significantly longer in group 5 compared with groups 1, 2, and 3 (p < 0.05), and operative mortality in group 5 (20%) was significantly higher than that in the other four groups. The mean total charges for group 5 were $73,399, which was significantly higher than the totals in the other four groups (p < 0.05). Actuarial 3-year survival for the hospital survivors was 87%, 89%, 78%, 82%, and 60% for groups 1, 2, 3, 4, and 5, respectively (p < 0.001). Postoperative performance as measured by the Karnofsky scale was significantly lower in group 5 than in groups 1 and 2 (p < 0.05). These data support the premise that elderly patients undergoing coronary artery bypass grafting have more complications, longer hospitalizations, and higher operative mortality than younger patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Eight years' experience with bridging to cardiac transplantation.

Although bridging to cardiac transplantation has become a therapeutic option for transplant candidates whose condition deteriorates while they are awaiting a donor heart, short-term efficacy has not been proved and long-term survival has not been reported. We retrospectively reviewed data on 44 patients who had circulatory assist devices placed as a bridge to transplantation between May 1985 and April 1993. The 35 male and nine female patients ranged in age from 12 to 65 years (mean 43.8 years). Thirty-one patients were supported with 32 Thoratec (18 left ventricular, 14 biventricular), 11 Novacor, and two Jarvik J-7-70 devices. The duration of device support was from 4 hours to 440 days (mean 45.5 days). Fifteen patients did not receive a donor organ because of infection (ten patients), renal failure (five patients), bleeding (nine patients), cerebrovascular accident (three patients), ventricular fibrillation (one patient), and right heart failure (one patient), and all died. Two patients were weaned from support and survived without transplantation. Twenty-seven patients underwent transplantation, and 26 survived (96%). Overall survival was 64% (28/44). Duration of survival ranged from 2 to 96 months (mean 35 months). Among the 28 hospital survivors, there were four late deaths (all transplant recipients) at 3, 6, 14, and 68 months. Posttransplantation actuarial survivals at 1, 5, and 8 years are 88%, 83%, and 66%. Twenty-three of the 24 patients presently alive are in New York Heart Association functional class I. These data demonstrate the short- and long-term efficacy of bridging to transplantation with circulatory support devices. The excellent survival and full functional recovery of patients undergoing transplantation ensure that donor organs are not being "wasted" on the sickest patients.

Reinfusion potassium blood cardioplegia versus cold blood reinfusion alone in elective revascularization.

The purpose of this study was to determine if the addition of potassium to reinfusion cold blood cardioplegia (CBC) offers an advantage over cold blood alone. Forty patients matched for age, left ventricular function, extent of coronary disease and number of vessels bypassed were prospectively randomized. Each patient received an initial dose of CBC (10 cc/kg) with potassium. Group I patients (n = 23) received subsequent infusions of CBC (5 cc/kg) containing potassium while Group II patients (n = 17) received cold blood only. The cross-clamp time, mean infusate volume and temperature were not significantly different in the two groups. Following reperfusion, the cardiac index and the CPK isoenzyme release at 0.5, 1, 8, and 12 h after cross-clamp release were not significantly different between the groups. The postoperative appearance of new Q-waves, inotropic agent requirement, and reversal of the lactate dehydrogenase (LDH) isoenzyme ratio were also not significantly different in the two groups. The study demonstrated that following initial arrest with potassium, cold blood is equally as effective as potassium blood cardioplegia in protecting the ischemic myocardium.

Vascular complications from intraaortic balloons: risk analysis.

PURPOSE: The purpose of this study was to assess the incidence of and predictors for vascular complications in patients who required perioperative intraaortic balloon pump (IABP) support. METHODS: Data from 580 patients collected with a retrospective review were statistically analyzed with 25 perioperative parameters, and significant variables were evaluated with multivariate analysis. These data were also statistically compared with data from a 1983 study from our institution. RESULTS: Vascular complications occurred in 72 patients (12.4%). The three aortic perforations were fatal. Ipsilateral leg ischemia occurred in 69 patients. Of these, ischemia was resolved in 82% of patients by IABP removal (21), thrombectomy (21), vascular repair (13), fasciotomy (2), or without intervention (2). Six patients died with the intraaortic balloon in place. Four patients required amputation for ischemia, but all survived. CONCLUSIONS: Vascular complications were not predictive of operative death (p = 0.26). Risk analyses with 25 perioperative parameters revealed that history of peripheral vascular disease, female sex, history of smoking, and postoperative insertion were independent predictors of vascular complications. However, most risk for vascular complications cannot be explained by these factors because of a low R2 value. Compared with the results of our 1983 study, the incidence of IABP-related complications has not changed, but the severity of complications has decreased significantly, and IABP-induced death has decreased significantly.

Vascular rejection in heart transplant recipients.

Antibody medicated (vascular) rejection has recently been described in heart transplantation. We report our experience with vascular rejection in a series of 62 patients who did not receive perioperative lymphocyte antibody therapy. Sixty-five rejections were reported, of which 58 (89%) were pure cellular; five (8%) had both cellular and vascular components, and two (3%) had only vascular rejection. Vascular rejection was very common in patients in whom hemodynamic compromise developed, and hemodynamic compromise was significantly more common in vascular than cellular rejection. Treatment for vascular rejection included plasmapheresis, intravenous methylprednisolone, and cyclophosphamide. Only one death occurred in this series, and that occurred in a patient with vascular rejection where the diagnosis and initiation of therapy were delayed. The role of vascular rejection in patients with hemodynamic compromise is discussed.

Inferior epigastric artery for myocardial revascularization.

From March 1990 through January 1992, 108 patients undergoing myocardial revascularization had one (91) or both (17) inferior epigastric arteries (IEA) used for myocardial revascularization. The internal thoracic artery (ITA) was used bilaterally in 87 patients. Of the 373 distal anastomoses, 210 (56%) were with the ITA, 130 (35%) with the IEA, and 12 (3%) with the gastroepiploic artery. Nineteen patients (18%) received 21 saphenous veins. When compared with the ITA, the IEA demonstrated a longer harvest time (36.5 vs 29.6 min, P < 0.0001), a shorter usable length (11.9 cm vs 16.5 cm, P < 0.001), and similar flow (49.7 cc/min vs 48.7 cc/min, P = NS). The operative mortality was 2.8%. Two deaths resulted from low cardiac output and the one remaining death from complications of a cerebral vascular accident. The most common major complication was respiratory insufficiency, which occurred in 11 patients (12%). There were two sternal infections (2%), and two abdominal wound infections (2%), none of which were fatal. The IEA is an acceptable additional arterial conduit. It can be safely employed with one or both ITAs. Short-term and long-term patency must be established before preferential use of this conduit is advised.

Intraaortic balloon pumping in patients requiring cardiac operations. Risk analysis and long-term follow-up.

The intraaortic balloon pump is usually the first mechanical device inserted for perioperative cardiac failure; however, little current information is available regarding short- and long-term effectiveness. From January 1983 through November 1990, 6856 adult patients underwent cardiac surgical procedures, 580 of whom (8.5%) had an intraaortic balloon inserted preoperatively (107 patients), intraoperatively (419 patients), or postoperatively (54 patients). There were 374 men and 206 women with a mean age of 63.9 years (range 19 to 88). Operations included 376 coronary artery bypass grafts, 100 mitral valve replacements (with or without bypass grafting), 70 aortic valve replacements (with or without bypass grafting), 15 double valve replacements (with or without bypass grafting), and 32 other procedures. There were 72 (12.4%) complications related to the balloon pump, of which 42 necessitated surgical intervention including thrombectomy (21), vascular repair (13), fasciotomy (2), aortic repair (1), and amputation (4). Operative mortality for patients supported by the balloon pump was 44%. Multivariate stepwise analysis of 27 parameters revealed six independent predictors of mortality: preoperative New York Heart Association class, transthoracic intraaortic balloon insertion (both p < 0.0001), preoperative administration of intravenous nitroglycerin, age, female gender, and preoperative balloon insertion (p < 0.001). Balloon-related complications were not predictive of death. Of the 326 hospital survivors, only 34 were lost to follow-up. There were 75 late deaths, the cause of which was cardiac in 41 (55%), noncardiac in 20 (27%), and unknown in 14 (19%). Actuarial survivals at 1, 5, and 9 years are 51%, 42%, and 33%. Of the 217 hospital survivors still alive and contacted, 81% were in class I (114) or II (60). These data demonstrate (1) operative mortality for patients requiring an intraaortic balloon in the perioperative period remains high, (2) perioperative risk factors can be identified, (3) complications related to the balloon pump do not affect survival, (4) operative survivors can achieve prolonged survival with excellent functional results, and (5) consideration for alternative methods of circulatory support is justified.

Mitral valve replacement: randomized trial of St. Jude and Medtronic-Hall prostheses.

To better define the merits of the bileaflet and tilting-disc valves, we prospectively randomized 102 patients (mean age, 57 years; range, 11 to 85 years) to receive either the St. Jude (n = 55) or the Medtronic-Hall (n = 47) mitral valve prosthesis between September 1986 and May 1991. The two groups were not different with respect to preoperative New York Heart Association class, incidence of mitral stenosis and insufficiency, angina score, extent of coronary artery disease, ventricular function, completeness of revascularization, or cross-clamp or bypass time. The hospital mortality (14.5% versus 10.6%, St. Jude versus Medtronic-Hall) and late mortality (7.3% versus 2.1%) were not significantly different. Follow-up was complete in 84 of 89 hospital survivors (94%) with a mean of 26 months (range, 1 to 60 months). The linearized rates of valve-related events and the 3-year actuarial survival demonstrated no significant differences between both cohorts. Comparison of the clinical outcome and echocardiographic parameters obtained at the time of follow-up demonstrated no significant differences between the two prostheses. These data indicate that the Medtronic-Hall and St. Jude mitral prostheses are similar with respect to their rates of valve-related complications and hemodynamic profiles. This study suggests that there is no difference between the St. Jude and Medtronic-Hall prostheses with regard to early clinical performance or hemodynamic results and therefore does not support the preferential selection of either prosthesis.

Successful withdrawal of corticosteroids in heart transplantation.

The ability to withdrawal corticosteroids from the maintenance immunosuppression regimen has been reported in heart transplant recipients. Most patients tested have had corticosteroids discontinued by 3 to 4 weeks after transplantation and have received perioperative administration of lymphocyte antibody therapy. To assess the importance of the additional "induction" therapy and the comparative results of delaying steroid withdrawal until after most rejections had occurred in our program, we withdrew maintenance steroids from 48 patients who were an average of 11 months (median, 8.6 months, range, 5 to 59 months) after transplantation. Mean patient age was 48 years, 95% were men, and 60% of the patients had never been treated for rejection before steroid withdrawal. Forty of the 48 patients (82%) were successfully withdrawn and remain free of steroids with an average of 25 months (range, 5 to 39 months) of follow-up off steroids. Ten episodes of rejection occurred in eight patients (82% rejection free). Six patients had a single rejection and two had more than one rejection. The average time to rejection after steroid withdrawal was 4 1/2 months, but two patients developed their first-ever rejection at 11 1/2 and 12 1/2 months after steroid withdrawal. Three of the rejections after steroid withdrawal were treated with intravenous steroids (10 mg/kg/day for 3 days) without a return to maintenance steroids. These three patients have not had a subsequent episode of rejection in 15 months of follow-up. The other three patients with rejection were returned to steroid therapy because of an inability to tolerate azathioprine, as were three patients without rejection for unrelated reasons.(ABSTRACT TRUNCATED AT 250 WORDS)

Load dependence of the effective regurgitant orifice area in a sheep model of aortic regurgitation.

Treatment of patients with aortic regurgitation with vasodilators reduces regurgitant volume, ventricular dilation and left ventricular mass. Although these effects are presumably due to afterload reduction, it is also possible that the aortic regurgitant orifice area is not constant. To test the latter hypothesis, aortic regurgitation was created in 10 open chest sheep by partial resection of the noncoronary leaflet under direct visualization. Regurgitant flow was measured with an aortic supravalvular electromagnetic probe; aortic and left ventricular pressures were measured with catheter-tipped micromanometer pressure transducers. The effective regurgitant orifice area was calculated by a modification of the continuity equation in a manner similar to the Gorlin equation. The regurgitant orifice area was measured three times: after aortic regurgitation was created, after mean arterial pressure was increased by 15 to 25 mm Hg with intravenous dopamine and after mean arterial pressure was reduced by 15 to 25 mm Hg with intravenous sodium nitroprusside. Comparison of regurgitant volumes and areas obtained after creation of aortic regurgitation and at the conclusion of the experiment in the absence of dopamine or sodium nitroprusside demonstrated no significant change over time. Dopamine administration was associated with an 86 +/- 81% increase in regurgitant volume (p less than 0.01) and a 38 +/- 44% increase in regurgitant orifice area (p less than 0.01). Sodium nitroprusside administration resulted in a 51 +/- 14% decrease in regurgitant volume (p less than 0.001) and a 28 +/- 21% reduction in regurgitant orifice area (p = 0.007). In this model of acute aortic regurgitation, the effective regurgitant orifice area was altered by increasing or decreasing the aortic transvalvular pressure gradient.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of ventricular arrhythmias in bridge patients with ventricular assist devices.

To evaluate whether bridge to transplant patients with ventricular arrhythmias (VA; fibrillation or tachycardia) are at risk of death before or during ventricular assist device (VAD) support, the records of 28 patients who were supported with VADs for periods of 0.1 to 370 days (mean, 35.3 days) were retrospectively reviewed. VADs were effective in reducing the incidence of VA by 36%; however, patients with ischemic heart disease had a high incidence of VA (44%) during VAD. Only one patient with non-ischemic heart disease (8%) had VA during VAD. All five patients supported with left ventricular assist devices who had VA during support survived. Overall, the occurrence of VA during VAD was not a mortality risk. Since VAs are not predictors of survival, the presence of VA should not influence patient selection. While biventricular assist devices may be necessary in patients with the most severe VA, an LVAD provides excellent support in many patients.

Pulmonary artery balloon counterpulsation for intraoperative right ventricular failure.

Two cases of severe low cardiac output and right ventricular failure after coronary artery bypass grafting necessitated pulmonary artery balloon counterpulsation after intraaortic balloon pumping and maximal inotropic/pressor support were unsuccessful in maintaining a satisfactory cardiac output. Hemodynamic improvement was sufficient to allow removal of the device 2 and 3 days postoperatively, with survival in 1 patient. Pulmonary artery counterpulsation is less morbid in comparison with other mechanical methods of right ventricular support and is applicable in right ventricular failure of intermediate severity.

Fifteen-year follow-up for double internal thoracic artery grafts.

The internal mammary artery (IMA) is the conduit of choice for myocardial revascularization. From 1972 to 1989, 586 patients received bilateral IMA and supplemental vein grafts. There were 506 men (86%) and 79 women (14%) with a mean age of 55.5 years (range 32-77 years). Unstable angina was present in 138 patients (24%), insulin-requiring diabetes mellitus in 83 (14%) and previous myocardial infarction (MI) in 25 (4%). Preoperative angiography demonstrated triple-vessel disease in 286 patients (49%) and double-vessel disease in the remaining 300 patients (51%). Left main coronary artery disease (stenosis greater than or equal to 50%) was present in 53 (9%). The mean left ventricular score was 7.4 with a range of 5 to 20. The mean number of grafts performed was 3.4 per patient. Hospital mortality was 3.6% (21 patients). Follow-up was done through direct patient contact, via the patient's physician or by telephone contact with the patient themselves or surviving family members. Follow-up was complete in 518 hospital survivors and ranged from 1 month to 17.5 years with a cumulative follow-up of 911 patient years. At 10 and 15 years, respectively, the actuarial freedom from MI was 78% and 72% and freedom from reoperation was 93% and 86%. Actuarial survival at 10 and 15 years was 85% and 70%, respectively. This longitudinal analysis demonstrates that bilateral IMA grafting has a low operative risk. The data suggest that utilization of two IMA grafts yield excellent freedom from recurrent symptoms and provides excellent long-term survival.

Coronary bypass grafting with totally calcified or acutely dissected ascending aorta.

From August 1984 through November 1988, 10 of 2,658 patients undergoing coronary artery bypass grafting had ascending aortic disease that was not amenable to proximal anastomoses for coronary bypass grafting. This was due to a calcified aorta in 6 and acute aortic dissection in 4. There were 5 male and 5 female patients with a mean age of 71 years. Cannulation site was the femoral artery in 5, ascending aorta in 3, and aortic arch in 2. Profound hypothermia and ventricular fibrillation, with no cross-clamp or cardioplegia, was used in 9 patients, and circulatory arrest in 1. In 8 patients a single internal mammary artery was used as the total inflow with a saphenous vein graft brought off the internal mammary artery to one or more distal left-sided coronary vessels. Bilateral internal mammary arteries were used in 2 other patients. Operative mortality was zero. There was one perioperative myocardial infarction and one transient stroke without sequelae. All patients have done well from 1 to 6 years postoperatively. These data support the use of internal mammary arteries as single or bilateral proximal conduits for other venoarterial bypass grafts when the aorta is extensively diseased either by calcification or dissection.

Neurological and ophthalmological phenomena after aortic conduit surgery.

Transient neurological and visual signs have been observed in some patients after valved conduit replacement of the aortic valve and ascending aorta. Twenty-seven patients having valved conduit replacement between February 1982 and October 1988 were compared with 21 patients having combined aortic valve replacement (AVR) and ascending aorta (AA) graft replacement. Follow-up in 100% of both groups was obtained for 0.3-6.6 years (mean, 2.6 +/- 0.3 years). Among 20 surviving valved conduit patients, 10 (50.0%) experienced repetitive neurological and visual signs, including scotomata (seven), transient motor ischemic attacks (two), amaurosis fugax (four), and recurring attention lapses suggesting petit mal seizures (one). No patient with AVR + AA graft experienced any events (p = 0.004). All valved conduit and seven (53.8%) of AVR + AA graft patients were on warfarin (p = 0.0016). These events retained the same pattern although they diminished in frequency after 12 months in seven patients (70.0%) and after initiation of dipyridamole in two patients. Rehabilitation was similar in both groups: 18 of 20 (90.0%) valved conduit and 12 of 16 (75.0%) AVR + AA graft patients (p = NS). Transient, repetitive, nonprogressive neurological and ophthalmological phenomena are frequent after valved conduit replacement. The pathophysiological mechanism is unclear, but antiplatelet therapy may provide symptomatic control.

Favorable results of coronary artery bypass grafting in patients older than 75 years.

There is controversy whether the short-term and long-term results of coronary artery bypass grafting in elderly patients justify performing the procedure. Between January 1977 and December 1986, 4580 patients underwent coronary artery bypass grafting, of whom 222 (4.9%) were 75 years old or older (mean 77 years). There were 143 men and 79 women and 139 (63%) were in New York Heart Association class IV. One hundred forty-six patients (66%) had had at least one preoperative myocardial infarction. Myocardial revascularization was performed under emergency conditions in 17 patients (18%). The mammary artery was used in 43%, 96% of the patients received two or more grafts. The mean number of bypass grafts was 3.1 per patient. The overall hospital mortality rate was 10.8% (24/222), 3.6% for elective procedures, 14.9% in urgent cases, and 35% in emergencies. In contrast, the overall early mortality rate was 3.1% in 4358 patients less than 75 years old. Complications occurred in 83 patients (37%). Of the patients discharged from the hospital, 198 were followed up for a mean of 48 months (1 to 130). Actuarial probability of survival was 75% at 48 months. Postoperatively 70% were in New York Heart Association class I or II and only 21% were rehospitalized for cardiac problems. During the follow-up period 77% of the patients were free from angina, and of those experiencing angina the mean time from operation to the first episode was 75 months. Although elderly patients have a somewhat increased operative mortality rate, particularly if operated on urgently or emergently, long-term survival and freedom from angina are excellent and justify continued performance of coronary bypass grafting in selected patients over 75 years of age.

Mitral valve repair for myxomatous degeneration and prolapse of the mitral valve.

From 1984 to 1988, 129 mitral valve reconstructions were done for primary pure mitral regurgitation. Sixty-two (48%) were done for myxomatous degeneration and prolapse of the mitral valve. Anterior leaflet resection was performed in seven patients, posterior leaflet resection in 46, anteroposterior resection in four; five patients received only a ring annuloplasty. Eight patients had coronary bypass grafts. Twenty-four patients received a Carpentier-Edwards annuloplasty ring, 24 a Duran ring, and 14 patients had no ring. Follow-up was 1 to 50 months (mean, 13 months). No patient was lost to follow-up. There was one operative death from gastrointestinal bleeding and two late deaths (one from suicide and one from a myocardial infarction), and the probability of survival at 48 months was 84% +/- 15%. There were no thromboembolic episodes or episodes of endocarditis. However, there were five reoperations (9%) with freedom from reoperation at 48 months of 85% +/- 5%. There was one major anticoagulant hemorrhage. Freedom from all morbidity at 48 months was 81% +/- 8%. Postoperative echocardiographic data in the three different groups of patients undergoing repair on the basis of annuloplasty treatment showed that the peak gradient was less and the valve area was slightly greater with no annuloplasty ring.