Pravastatin improves endothelial function in arteries used in coronary bypass grafting.

Internal mammary artery (IMA) and radial artery (RA) are the 2 main arterial conduits used in coronary artery bypass grafting (CABG). The aim of this study was to analyze in vitro the vasoreactive properties in both vessels and to investigate the effects of pravastatin incubation on vascular function. IMA and RA rings obtained from patients undergoing CABG were studied in organ baths. We examined the contractile responses to phenylephrine and U46619 and the relaxation to acetylcholine (ACh) and sodium nitroprusside. In another series of experiments, the vascular reactivity and the superoxide anion production were studied after incubation with pravastatin. The effect of mevalonic acid on such responses was also assessed. Our results show that RA significantly evoked greater tension in response to vasoconstrictor agents and higher relaxation to ACh than IMA. In contrast, relaxation induced by sodium nitroprusside was not significantly different. Incubation with pravastatin reduced the contractile response to U46619 and improved the endothelium-dependent relaxation to ACh in both arteries. Whereas the effect of pravastatin on response to U46619 was completely abolished by coincubation with mevalonic acid, only a partial inhibition on ACh relaxation was observed. In conclusion, in vitro incubation with pravastatin enhanced endothelial function in IMA and RA. This suggests that postoperative (may include intraoperative) administration of statins could improve the endothelial function of arterial grafts in patients undergoing CABG.

Prognostic value of chronic obstructive pulmonary disease in coronary artery bypass grafting.

OBJECTIVE: Coronary and chronic lung diseases have become a common association. This comorbidity has been generically considered by most of the operative risk scores, but its functional severity has seldom been addressed by these models. Our objective was to analyze its prognostic relevance considering preoperative pulmonary function parameters. METHODS: All patients undergoing CABG from May 1993 to December 2004 have been reviewed. One thousand four hundred and twelve patients with preoperative pulmonary function test were finally included in the study. Obstructive lung disease was defined when FEV1/FVC<0.7. In-hospital mortality and complication rate related to chronic obstructive pulmonary disease and its degree of severity (FEV1%) were assessed. Logistic regression analysis was used to determine independent predictors of mortality. RESULTS: A pathologic preoperative pulmonary function test was found in 39% of patients: obstructive in 26% (FEV1/FVC<0.7), restrictive in 9% and combined obstructive-restrictive in 4%. In-hospital mortality was higher in patients with abnormal test: 6.5% versus 0.9% (p<0.001). Mortality was clearly related with the severity of lung disease: 0.9% in patients with FEV1: >80%, 0.4% in FEV1: 60-80%, 10.8% in FEV1: 40-59% and 54% in FEV1: <40%. In the latter group, other intercurrent prognostic factors were observed. Patients with FEV1<60% had higher mortality than those with FEV1>60%: 24.6% versus 1.4% (p<0.001). Chronic obstructive lung disease was not an independent predictor of mortality but FEV1< or =60% was significantly associated with death. CONCLUSIONS: This study on chronic lung comorbidity in CABG patients shows that this association can be of deleterious prognostic value but this effect is directly related to the degree of functional severity. Preoperative FEV1<60% must be considered as a primary prognostic factor in patients undergoing CABG procedures.

Patient-prosthesis mismatch in aortic valve replacement: really tolerable?

OBJECTIVE: Several studies have demonstrated favorable results despite patient-prosthesis mismatch after aortic valve replacement with the use of third generation prostheses. Our aim was to determine whether this mismatch is always tolerable. METHODS: A clinical-echocardiographic study has been performed in 339 consecutive patients who underwent aortic valve replacement because of aortic stenosis. In-hospital outcome and left ventricular mass index regression (1st month-1st year) were analyzed in the presence or absence of mismatch (indexed effective orifice area < or =0.85cm(2)/m(2)). The influence of high degrees of preoperative left ventricular mass on in-hospital mortality has also been evaluated. Left ventricular mass index was considered increased if the calculated value was over the superior quartile of the frequency distribution of all the values observed in both sexes. RESULTS: Mismatch was found in 38% of the patients. In the absence of mismatch, the absolute mass regression was proportional to the preoperative left ventricular mass. This regression was higher in patients with increased left ventricular mass indexed (vs not increased): -38.0+/-7.8 vs -8.8+/-4.7g/m(2), p<0.01 (1st month) and -67.7+/-16.9vs -23.5+/-6.7g/m(2), p<0.05 (1st year). Mass regression was impaired in the presence of mismatch, particularly, in patients with previously increased left ventricular mass: -8.2+/-11.6 vs -5.6+/-6.3g/m(2) (p=0.83) and -24.6+/-12.6 vs -11.7+/-10.5g/m(2) (p=0.54). This worse regression was reflected on a 100% incidence of residual hypertrophy at follow-up (1st month-1st year). In the presence of mismatch, increased ventricular mass was associated with higher mortality: 14.7% vs 2.1% (p<0.01). In the absence of mismatch, ventricular mass was not associated with mortality: 4.1 vs 2.5% (p=0.55). CONCLUSIONS: In patients with severe ventricular hypertrophy it may be important to elude patient-prosthesis mismatch to avoid a significant increase in mortality and improve ventricular mass regression. Mismatch may be tolerable in those patients with lesser degree of hypertrophy.

Left ventricular mass index in aortic valve surgery: a new index for early valve replacement?

OBJECTIVE: Increased left ventricular mass index has been associated with higher mortality. We analyze the effect of increased left ventricular mass index on outcomes in patients undergoing aortic valve replacement. METHODS: Echocardiographic left ventricular dimensions were used to calculate left ventricular mass index in 614 patients who underwent aortic valve replacement between June 1993 and November 2001. Left ventricular mass index was considered increased if higher than the value of the superior decile (277 g/m(2) in males and 251 in females). RESULTS: Mean left ventricular mass index was: 178+/-111 g/m(2), and increased index was considered in 9.9% of patients. Postoperative complications (low cardiac output syndrome, respiratory failure, arrhythmias, pneumonia and mediastinitis), median length of hospital stay: 12 days (6-57) versus 11 days (5-51), and in-hospital mortality (11.4, 3.2%, P<0.01) were higher in patients with increased left ventricular mass index. Multivariable analysis identified increased left ventricular mass index (odds ratio: 5.6; 95% confidence interval: 1.2-25.0; P=0.02) and other three variables: age (P=0.04), history of chronic renal failure (P=0.03) and cardiopulmonary bypass time (P=0.004), as independent predictors of early mortality. CONCLUSIONS: Increased left ventricular mass index is associated with an in-hospital adverse outcome and a significantly higher in-hospital mortality in patients undergoing aortic valve replacement. Outcomes in asymptomatic patients could be improved before a clinically significant increase in left ventricular mass index. Further studies should be performed to determine the usefulness of this index in selecting patients for earlier aortic valve replacement.