Faculty Bibliography

Aim: To document the short- and long-term effects of mitral valve reconstruction in patients 70 years of age and older. Recent favorable experience with mitral-valve reconstructive techniques has led to an attempt to apply them to elderly patients with mitral-valve defects, in the hope of improving ventricular function and freedom from complications in this higher-risk group. Methods: Between lune 1980 and June 1993, 160 consecutive mitral-valve reconstructions were performed using Carpentier techniques on patients 70 years of age and older (n=140 for 70-79 years, n=20 for greater than or equal to 80 years). All procedures were for either pure mitral regurgitation or mixed stenosis/regurgitation and involved placement of an annuloplasty ring. Concomitant cardiac operative procedures were performed in 109 patients (68%), including coronary bypass grafting in 67 (42%) and other valve procedures in 27 (17%). Results: Hospital mortality was 5.9% (three out of 51) for isolated mitral-valve reconstruction and 11.9% (19 out of 160) overall. Before surgery, 89.4% of the patients were in New York Heart Association (NYHA) class III or IV. At follow-up, 89.1% were in NYHA class I or II. In patients who underwent an isolated mitral-valve operation, cumulative freedom from cardiac death and reoperation, including hospital death, was 85.9% at 5 years. Conclusions: These results demonstrate that the encouraging results seen to date in younger patients who have undergone mitral-valve reconstruction can also be achieved in elderly patients

Expansion of the vascular wall through formation of neointimal fibromuscular lesions is the basic mechanism underlying stenosis of vascular grafts, restenosis of arteries treated by balloon angioplasty, and other major cardiovascular problems. This study examined the effect of a single, systemic, low dose of basic fibroblast growth factor (bFGF) on formation of neointimal fibromuscular lesions in response to injury. New Zealand white rabbits (n = 76) were subjected to balloon injury of the abdominal aorta. Forty-five rabbits were given a single intravenous dose of bFGF (0.5 microgram/kg) immediately after injury, and 31 rabbits were given only the vehicle solution as controls. After 2 (n = 15), 5 (n = 21), 14 (n = 29), or 28 (n = 11) days the rabbits were sacrificed. Those rabbits receiving the single administration of bFGF exhibited significantly greater intimal thickening (intima/media ratio) than the control group at 5 days (mean +/- standard error of the mean, 0.091 +/- 0.009 versus 0.058 +/- 0.006; p < 0.002), but not at 14 or 28 days. These results were achieved without any significant differences in mitotic indices, as determined by a mitostatic method, between the two groups at any postinjury interval examined. The findings suggest that a single systemic dose of exogenous bFGF has a relatively long term effect on enhancing the neointimal response to vascular injury. Therefore, local control of endogenous bFGF may be useful in limiting formation of vascular neointimal fibromuscular lesions, thus improving the long-term results of vascular grafts, balloon angioplasty, and other cardiovascular procedures

Atheromatous disease in the transverse aortic arch is associated with an increased incidence of perioperative stroke. In addition, tissue erosion in the aortic arch is caused by the high-velocity jet emerging from an aortic cannula during cardiopulmonary bypass (CPB), termed the 'sandblast effect'. To quantify this phenomenon, flow in the aortic arch was measured intraoperatively by epiaortic ultrasonography in 18 patients undergoing CPB. All were cannulated in the ascending aorta, 10 with a short (1.5 cm) cannula and 8 with a long (7.0 cm) cannula. The peak forward aortic flow velocities (mean +/- standard deviation) measured on the caudal luminal surface of the aortic arch were 0.80 +/- 0.23 m/s off CPB and 2.42 +/- 0.69 m/s on CPB (p < 0.001) for the short cannula and 0.53 +/- 0.20 m/s off CPB and 0.18 m/s on CPB for the long cannula. Thus, during CPB the peak forward aortic flow velocity with the short cannula was significantly greater (p < 0.001) than before CPB, whereas the long cannula produced a lower peak forward aortic flow velocity during CPB. Furthermore, Doppler examination revealed severe turbulence in the aortic arch in all patients with a short cannula. No arch turbulence, however, was seen in 7 patients with a long cannula, and only mild turbulence appeared in the remaining patient with a long cannula. These results show that use of a long aortic cannula results in a significant decrease in peak forward aortic flow velocity and turbulence in the aortic arch during CPB, which may reduce the risk of erosion or disruption of existing atheroma and ensuing embolic complications

This experiment was designed to determine the relative degree of cardiac functional recovery provided by various forms of resuscitative retrograde blood cardioplegia after global ischemic injury. Twenty-four dogs were subjected to 20 minutes of normothermic global myocardial ischemia followed by 60 minutes of cardioplegic arrest by one of three methods: group 1, standard cold blood cardioplegia with a cold terminal dose (n = 8); group 2, aspartate-glutamate-enhanced blood cardioplegia with warm induction and terminal enhancement (n = 8); and group 3, continuous warm blood cardioplegia (n = 8). Sonomicrometry was used to analyze left ventricular function for maximal elastance and preload recruitable stroke work area. Data were recorded at baseline and after 30 and 60 minutes of unloaded reperfusion. The results showed improved early recovery of preload recruitable stroke work area, but not of maximal elastance, after reperfusion of ischemic hearts with warm resuscitative blood cardioplegic solution enhanced with amino acids. The functional improvement provided by this technique was transient, however, and no significant differences were detectable among the groups after 60 minutes of unloaded reperfusion. Neither amino acid enhancement nor continuous warm cardioplegia offered a significant advantage in functional recovery over the standard method of cold blood cardioplegia reperfusion

OBJECTIVES. This study was done to assess the impact of anterior mitral leaflet reconstructive procedures on initial and long-term results of mitral valve repair. BACKGROUND. It has been suggested that involvement of the anterior leaflet in mitral valve disease adversely affects the long-term outcome of mitral valve repair. Our policy has been to aggressively repair such anterior leaflets with procedures that include triangular resections in some cases. METHODS. From June 1979 through June 1993, 558 consecutive Carpentier-type mitral valve repairs were performed. The anterior mitral leaflet and chordae tendineae were repaired in 156 patients (mean age 58 years). The procedures included anterior chordal shortening in 78 patients (50%), anterior leaflet resections in 44 (28%), resuspension of the anterior leaflet to secondary chordae in 42 (27%) and anterior chordal transposition in 27 (17%). Concomitant cardiac surgical procedures were performed in 75 patients (48%). RESULTS. The operative mortality rate was 2.5% (2 of 81) for isolated mitral valve anterior leaflet repair and 3.8% (6 of 156) for all mitral valve anterior leaflet repair. Freedom from reoperation at 5 and 10 years was, respectively, 89.7% (n = 160) and 83.4% (n = 24) for the entire series of 558 patients, 91.9% (n = 51) and 81.2% (n = 10) for patients with anterior leaflet procedures, 88.8% (n = 109) and 84.4% (n = 14) for patients without anterior leaflet procedures and 91.7% (n = 118) and 88.9% (n = 18) for patients without rheumatic disease. Logistic regression showed that rheumatic origin of disease (odds ratio 2.99), but not anterior leaflet repair, increased the risk for reoperation. CONCLUSIONS. These results demonstrate that expansion of mitral valve techniques to include anterior leaflet disease yields immediate and long-term results equal to those seen in patients with posterior leaflet disease

In order to improve the understanding of the role of sympathetic nerve degeneration in reimplantation failure, the hindlimbs of eight rats (Group I) underwent near-complete amputation. The soft tissues of the hindlimb were transected at the proximal thigh with the femoral artery, vein and femur left intact. The femoral vessels were clamped and guanethidine was infused into a branch of the femoral artery of the right leg of each animal, while saline was injected into the left leg. The clamps were removed after 15 minutes. A baseline preoperative injection of radiolabeled microspheres was made, and subsequent injections at 6, 12, 18, and 24 hours postoperation. Twelve rats (Group II) were then used to assess the amount of arterial-venous shunting preoperatively (n = 6) and at 18 hours postoperation (n = 6), by venous sampling. Blood flow to both limbs increased postoperation, but there was significantly more flow in the guanethidine treated limb at 18 and 24 hours postoperation. The amount of shunting was approximately 50% in both limbs at 18 hours, as compared to 10% preoperation. These results highlight the potential benefit of guanethidine and other sympathetic blocking agents in reimplantation to increase blood flow, decrease tissue ischemia and increase anastomotic patency rates. They also suggest that sympathetic nerve degeneration did not affect the volume of arterial-venous shunting in this model, but the difference in blood flow was likely due to arteriolar vasospasm. Further study is needed to elucidate the clinical significance of sympathetic nerve degeneration in reimplantation failure

BACKGROUND: Although retrograde warm continuous cardioplegia (RWCC) has been recently advocated as a method of myocardial preservation during cardiac surgery, scant data exist on the effects of RWCC on right ventricular function. However, previous data have clearly shown that retrograde cardioplegia is poorly distributed to the right ventricle and interventricular septum. This experiment was performed to analyze functional preservation of the right ventricle after RWCC. METHODS AND RESULTS: Fourteen mongrel dogs were instrumented with sonomicrometers and pressure transducers to determine left and right ventricular (LV, RV) pressure-volume relationships and placed on cardiopulmonary bypass. All dogs underwent 90 minutes of aortic cross-clamping with either (1) RWCC (n = 7) after antegrade warm arrest or (2) retrograde cold multidose cardioplegia (RCMC) (n = 7) with topical hypothermia after antegrade cold arrest. All dogs received identical blood cardioplegia solutions. Ventricular function was measured before arrest and 30 and 60 minutes after unclamping. The end-diastolic-work area relationship was calculated, and the slope is presented as percent of baseline (mean +/- SEM; repeated measures ANOVA). At 30 minutes after unclamping, RWCC provided 68.77 +/- 9.09 for the left ventricle and 41.03 +/- 7.49 (P < .05 for RWCC versus RCMC for RV function at 30 minutes) for the right ventricle, and RCMC provided 62.80 +/- 7.23 for the left ventricle and 79.40 +/- 13.82 for the right ventricle. At 60 minutes after unclamping, RWCC provided 58.24 +/- 12.35 for the left ventricle and 48.05 +/- 9.72 for the right ventricle, and RCMC provided 65.38 +/- 6.76 for the left ventricle and 61.95 +/- 8.70 for the right ventricle. (P = NS for RWCC versus RCMC for LV function at either 30 or 60 minutes). These results demonstrate depressed recovery of RV function after 90 minutes of RWCC (P < .05 at 30 minutes after reperfusion) compared with RCMC. No difference in recovery of LV function was detected. CONCLUSION: RWCC may be harmful to the right ventricle and should be used with caution, particularly in patients with preexisting RV hypertrophy

BACKGROUND: To investigate the possibility of gender bias in the cardiac management of patients who undergo peripheral vascular surgery, we examined the hospital data and outcomes for 350 adult men and 128 women who underwent vascular surgery from September 1987 to December 1991. METHODS AND RESULTS: There were no significant differences between the two groups in age at operation, incidence of standard risk factors for myocardial infarction, or incidence or duration of episodes of perioperative silent ischemia. Nevertheless, a significantly lower percentage of women than men had undergone prior coronary bypass procedures (6.3% and 17.1%, respectively; P < .01), an apparent example of gender bias. However, there was no significant difference in the incidence of perioperative myocardial infarction in women (3.9%) compared with men (4.0%). Furthermore, actuarial analysis showed that at 24 months after operation a significantly higher percentage of women (77.9%) had escaped late cardiac death and cardiac complications than men (71.9%; P < .05). CONCLUSIONS: These findings indicate that apparent gender bias in the preoperative cardiac management of this group of women who underwent vascular surgery may have had no detrimental effect on short- and long-term incidence of cardiac death and complications, and may represent sound clinical judgment rather than true bias. However, the possibility that female patients might have had even better short- and long-term cardiac results if they had undergone more preoperative cardiac revascularization cannot be discounted

BACKGROUND: With the widespread application of mitral valve reconstructive techniques, systolic anterior motion (SAM) of the anterior mitral leaflet causing left ventricular outflow tract obstruction has been recognized by several groups. SAM occurred in 9.1% of the first 441 patients operated on for mitral valve reconstruction at our institution. Fortunately, SAM subsided with medical therapy within 1 year for a majority of patients as reported in May 1993. Some surgeons, however, have considered abandoning repair for prosthetic replacement after SAM was detected on intraoperative echocardiogram. METHODS AND RESULTS: Since June 1991, a triangular anterior leaflet resection has been cautiously evaluated in patients with extensive anterior leaflet tissue. This has been performed in 23 of 119 patients. CONCLUSIONS: The frequency of SAM in the 119 study patients has decreased from 9.1% to 3.4%