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Midwall fibrosis is an independent predictor of mortality in patients with aortic stenosis.

OBJECTIVES The goal of this study was to assess the prognostic significance of midwall and infarct patterns of late gadolinium enhancement (LGE) in aortic stenosis. BACKGROUND Myocardial fibrosis occurs in aortic stenosis as part of the hypertrophic response. It can be detected by LGE, which is associated with an adverse prognosis in a range of other cardiac conditions. METHODS Between January 2003 and October 2008, consecutive patients with moderate or severe aortic stenosis undergoing cardiovascular magnetic resonance with administration of gadolinium contrast were enrolled into a registry. Patients were categorized into absent, midwall, or infarct patterns of LGE by blinded independent observers. Patient follow-up was completed using patient questionnaires, source record data, and the National Strategic Tracing Service. RESULTS A total of 143 patients (age 68 ± 14 years; 97 male) were followed up for 2.0 ± 1.4 years. Seventy-two underwent aortic valve replacement, and 27 died (24 cardiac, 3 sudden cardiac deaths). Compared with those with no LGE (n = 49), univariate analysis revealed that patients with midwall fibrosis (n = 54) had an 8-fold increase in all-cause mortality despite similar aortic stenosis severity and coronary artery disease burden. Patients with an infarct pattern (n = 40) had a 6-fold increase. Midwall fibrosis (hazard ratio: 5.35; 95% confidence interval: 1.16 to 24.56; p = 0.03) and ejection fraction (hazard ratio: 0.96; 95% confidence interval: 0.94 to 0.99; p = 0.01) were independent predictors of all-cause mortality by multivariate analysis. CONCLUSIONS Midwall fibrosis was an independent predictor of mortality in patients with moderate and severe aortic stenosis. It has incremental prognostic value to ejection fraction and may provide a useful method of risk stratification.

Preoperative Angiotensin-Converting Enzyme Inhibitors and Acute Kidney Injury After Coronary Artery Bypass Grafting

BACKGROUND Angiotensin-converting enzyme (ACE) inhibitors confer renal protection in different clinical settings. No final conclusions are available on the renal benefits of ACE inhibitors after coronary artery bypass grafting (CABG). Because ACE inhibitors decrease glomerular perfusion pressure, they may exacerbate kidney injury during cardiopulmonary bypass (CPB)-related hypoperfusion. We evaluated the effect of preoperative ACE inhibitors on acute kidney injury (AKI) after CABG. METHODS A propensity score-based analysis of 536 patients undergoing CABG on CPB was performed, among which 281 received ACE inhibitors preoperatively. Patients with preoperative end-stage renal failure requiring dialysis were excluded. Postoperative AKI was defined as 50% or more decrease in the glomerular filtration rate from preoperative or postoperative mechanical renal support. RESULTS After CABG, AKI developed in 49 patients (9.1%), and 23 (4.2%) required dialysis. The incidence of AKI was 6.4% in patients who received preoperative ACE inhibitors and 12.2% in patients who did not (p = 0.02). The incidence of AKI requiring dialysis was 2.4% in the treatment group and 6.3% in controls (p = 0.03). After adjusting for propensity score and covariates, preoperative ACE inhibitors were found to reduce the incidence of postoperative AKI (odds ratio, 0.48; 95% confidence interval, 0.23 to 0.77; p = 0.04). Other independent predictors were age, preoperative glomerular filtration rate, left ventricular ejection fraction of less than 0.35, preoperative use of intraaortic balloon pump, emergency operation, and CPB time. CONCLUSIONS Preoperative ACE inhibitors are associated with a reduced rate of AKI after on-pump CABG surgery.

Radial artery versus saphenous vein graft patency: Meta-analysis of randomized controlled trials

The excellent patency rate achieved with the internal thoracic artery in coronary artery bypass grafting (CABG) prompted cardiac surgeons to explore other arteries as second conduits instead of the saphenous vein graft (SVG). Initially described in 1973 by Carpentier and colleagues, the radial artery (RA) was soon abandoned as a bypass graft because reports documented dismal early angiographic outcomes. Because of improvements in graft-harvesting techniques and the use of postoperative calcium-channel blocker therapy to prevent early vasospasm, the RA is newly popular as a second conduit in association with the left internal thoracic artery. However, concerns about the high incidence of RA graft failure caused by a compromised flow state continue to be raised. Thus ongoing debate remains regarding the superiority of the RA as an aortocoronary conduit over the SVG, which continues to be widely used as a second conduit. Therefore, we conducted a meta-analysis on available randomized controlled trials (RCTs) to evaluate whether the RA is associated with a better patency rate when compared with the SVG as a second conduit in CABG.

Miniaturized Cardiopulmonary Bypass and Acute Kidney Injury in Coronary Artery Bypass Graft Surgery

BACKGROUND Acute kidney injury (AKI) is one of the most important complications after on-pump coronary artery bypass graft surgery (CABG). Miniaturized cardiopulmonary bypass (mini-CPB) systems have been developed to allow the ease of on-pump surgery but tempering the disadvantages. Whether mini-CPB reduces the incidence of AKI remains to be determined. METHODS Using a propensity score matched analysis, we investigated the occurrence of AKI among patients undergoing CABG on mini-CPB (n = 104) versus conventional CPB (n = 601). Acute kidney injury was defined according to the recent Acute Kidney Injury Network classification. RESULTS Overall, acute kidney injury developed in 274 of 705 patients (38.8%). A total of 27 of 705 patients (3.8%) required renal replacement therapy. The median postoperative length of intensive care unit stay in survivors with AKI was 5.4 (3.9 to 6.8) days compared with 2.0 (1.0 to 3.0) days for patients without AKI (p = 0.0002). The overall incidence of AKI for patients undergoing mini-CPB was 30 of 104 (28.8%) compared with 244 of 601 (40.5%) for patients undergoing conventional CPB (p = 0.03). In the propensity score matched-pair statistical analysis, mini-CPB was independently associated with a decreased incidence of AKI (adjusted odds ratio [OR] 0.61; 95% confidence interval [CI]: 0.38 to 0.97). Other variables independently associated with AKI were preoperative glomerular filtration rate (OR 0.988 for 1 mL.min(-1).1.73 m(-2) increase; 95% CI: 0.98 to 0.99), postoperative red blood cell transfusion (OR 1.58; 95% CI: 1.12 to 2.23); CPB time (OR 1.005 for 1-minute increase; 95% CI: 1.0 to 1.009), and postoperative low output syndrome (OR 1.72; 95% CI: 1.23 to 2.41). CONCLUSIONS The present study showed that mini-CPB is associated with a lower incidence of AKI when compared with conventional CPB among patients undergoing CABG.

Preoperative angiotensin-converting enzyme inhibitors protect myocardium from ischemia during coronary artery bypass graft surgery

OBJECTIVES Coronary artery bypass graft surgery may result in perioperative myocardial injury during cardioplegic arrest. Angiotensin-converting enzyme (ACE) inhibitors protect the myocardium from ischemia in several clinical conditions, but no previous study has attempted to evaluate the impact of preoperative ACE inhibitor therapy on myocardial protection in patients undergoing coronary artery bypass graft surgery. METHODS A propensity score-based analysis of 481 patients undergoing isolated on-pump coronary artery bypass graft surgery was carried out, among which 245 patients received preoperative ACE inhibitors and 236 patients did not. Perioperative myocardial injury was assessed by ischemia marker cardiac troponin I (cTnI). RESULTS Preoperative cTnI concentration was similar for patients receiving ACE inhibitors and those who did not [0.1 ng/ml (0.06-0.19) versus 0.1 ng/ml (0.06-0.19); P = 0.3]. Postoperative cTnI peak concentration was lower in patients receiving preoperative ACE inhibitors [1.6 ng/ml (1.05-3.4) versus 2.4 ng/ml (1.13-6.10); P = 0.0006]. After adjusting for propensity score and covariates, preoperative ACE inhibitors were found to decrease postoperative cTnI peak concentration (beta = -0.12; P = 0.004). Other independent predictors of postoperative cTnI peak concentration were female gender, emergency surgery, number of distal anastomoses and aortic cross clamp time. Overall, operative mortality rate was 16/481 (3.3%). Patients receiving preoperative ACE inhibitors had a lower rate of postoperative myocardial infarction (2.0 versus 4.2%; P = 0.25) and low cardiac output syndrome (3.6 versus 6.3%; P = 0.24). CONCLUSION ACE inhibitors prior to surgery confer added myocardial protection during surgical revascularization. Prospective, randomized clinical trials will be necessary to better define the role of ACE inhibitors in improving outcomes when they are prescribed prior to coronary artery bypass graft surgery.Objectives Coronary artery bypass graft surgery may result in perioperative myocardial injury during cardioplegic arrest. Angiotensin-converting enzyme (ACE) inhibitors protect the myocardium from ischemia in several clinical conditions, but no previous study has attempted to evaluate the impact of preoperative ACE inhibitor therapy on myocardial protection in patients undergoing coronary artery bypass graft surgery. Methods A propensity score-based analysis of 481 patients undergoing isolated on-pump coronary artery bypass graft surgery was carried out, among which 245 patients received preoperative ACE inhibitors and 236 patients did not. Perioperative myocardial injury was assessed by ischemia marker cardiac troponin I (cTnI). Results Preoperative cTnI concentration was similar for patients receiving ACE inhibitors and those who did not [0.1 ng/ml (0.06–0.19) versus 0.1 ng/ml (0.06–0.19); P = 0.3]. Postoperative cTnI peak concentration was lower in patients receiving preoperative ACE inhibitors [1.6 ng/ml (1.05–3.4) versus 2.4 ng/ml (1.13–6.10); P = 0.0006]. After adjusting for propensity score and covariates, preoperative ACE inhibitors were found to decrease postoperative cTnI peak concentration (β = −0.12; P = 0.004). Other independent predictors of postoperative cTnI peak concentration were female gender, emergency surgery, number of distal anastomoses and aortic cross clamp time. Overall, operative mortality rate was 16/481 (3.3%). Patients receiving preoperative ACE inhibitors had a lower rate of postoperative myocardial infarction (2.0 versus 4.2%; P = 0.25) and low cardiac output syndrome (3.6 versus 6.3%; P = 0.24). Conclusion ACE inhibitors prior to surgery confer added myocardial protection during surgical revascularization. Prospective, randomized clinical trials will be necessary to better define the role of ACE inhibitors in improving outcomes when they are prescribed prior to coronary artery bypass graft surgery.

Is minimized extracorporeal circulation effective to reduce the need for red blood cell transfusion in coronary artery bypass grafting? Meta-analysis of randomized controlled trials

DISCUSSION The patient described had parietal pericardial bovine bioprostheses in both the mitral and aortic valve positions for 77 months and during that period developed huge quantities of calcium on the cusps of the bioprosthesis in the aortic valve position and only small quantities of calcium on the cusps of the bioprosthesis in the mitral valve position. Because the closing pressure on the mitral bioprosthesis is usually about a third higher than that on the aortic bioprosthesis (peak left ventricular systolic pressure vs end-diastolic aortic pressure; normally approximately 120 vs 80 mm Hg), it might be expected that the degeneration of a bioprosthesis in the mitral position would be greater (more calcium and more tears) and more rapid than that of a bioprosthesis in the aortic position, but the opposite was the case in the patient described herein. Why might that be the case? Some possibilities include the following:

Metabolic Syndrome Affects Midterm Outcome After Coronary Artery Bypass Grafting

BACKGROUND Metabolic syndrome (MetS) is frequently associated with coronary artery disease, but data on the impact of MetS on long-term outcome of patients undergoing coronary artery bypass grafting are still lacking. The aim of the present study was to assess the effect of MetS on mortality and morbidity late after coronary artery bypass grafting. METHODS A total of 1,726 consecutive patients who had elective coronary artery bypass grafting were retrospectively reviewed and clinical follow-up was completed (mean follow-up time, 34.4 months; range, 6 to 79 months). The MetS was diagnosed using the modified Adult Treatment Panel III criteria, and to eliminate covariate differences, a propensity score adjustment was used. Major adverse cerebral and cardiovascular events were investigated, and C-reactive protein levels were assessed both preoperatively, postoperatively, and at follow-up. RESULTS A total of 798 of 1,726 patients (46.2%) met the diagnostic criteria for MetS. At follow-up, all-cause mortality (7% versus 4.6%; p=0.04), cardiac arrhythmias (35.3% versus 25.2%; p<0.0001), renal failure (12% versus 8.7%; p=0.03), and major adverse cerebral and cardiovascular events (52.4% versus 39.5%; p<0.0001) showed a significantly higher incidence in MetS patients. Variables correlated with late mortality at propensity-adjusted Cox proportional-hazards regression were age (p=0.0008), preoperative left ventricular ejection fraction (p=0.001), preoperative renal failure (p=0.001), and MetS (p=0.006). Higher C-reactive protein levels were found preoperatively (8.6±2.3 versus 5.14±3.1 mg/L; p<0.0001) and both early (71.2±9 versus 49.6±8.7 mg/L; p<0.0001) and late (7.4±2.7 versus 4.8±2.5 mg/L; p<0.0001) after surgery. CONCLUSIONS The main finding of our study was the association between MetS and mortality both early and late after coronary artery bypass grafting. Thus, MetS should be recognized as an independent preoperative variable that can lead to the identification of high-risk patients and as a risk factor to correct with lifestyle modifications and pharmacologic therapy.

Impact of Prosthesis-Patient Mismatch on the Regression of Secondary Mitral Regurgitation After Isolated Aortic Valve Replacement With a Bioprosthetic Valve in Patients With Severe Aortic Stenosis

Background— Secondary mitral regurgitation (SMR) is generally reduced after isolated aortic valve replacement (AVR), but there is important interindividual variability in the magnitude of this reduction. Prosthesis-patient mismatch (PPM) may hinder normalization of left ventricular geometry and pressure overload following AVR, therefore we aimed to investigate the relationship between PPM and regression of SMR following AVR for aortic valve stenosis. Methods and Results— A total of 419 patients with AS who underwent isolated AVR at 2 institutions and presenting moderate SMR (mitral regurgitant volume 30 to 45 mL/beat) not considered for surgical correction were included in this study. Clinical and echocardiographic follow-up were completed at a median follow-up time of 37 months. PPM was defined as an indexed effective orifice area ⩽0.85 cm2/m2 and was found in 170/419 patients (40.6%). There were no significant differences in baseline and operative characteristics between patients with or without PPM. Patients with PPM had less regression of SMR following AVR compared with those with no PPM (change in mitral regurgitant volume:−11±4 versus −17±5 mL, respectively; P<0.0001). Variables significantly associated with postoperative change in mitral regurgitant volume on univariable analysis were entered in a multivariable linear regression model, which showed indexed effective orifice area (P<0.0001) and left atrial diameter (P=0.006) to be independently associated with mitral regurgitant volume improvement. Patients with PPM also had less postoperative improvement in 6-minute walking test distance (80±78 versus 42±41 m, P<0.0001). Conclusions— PPM is associated with lesser regression of SMR following AVR. This unfavorable effect was associated with worse functional capacity. These findings emphasize the importance of operative strategies aiming to prevent PPM in patients with aortic valve stenosis and concomitant SMR.

β-Blockers Improve Survival of Patients With Chronic Obstructive Pulmonary Disease After Coronary Artery Bypass Grafting

BACKGROUND β-Blockers are known to improve survival of patients with cardiovascular disease, but their administration in patients with chronic obstructive pulmonary disease (COPD) remains controversial. The aim of the present study was to assess the effect of β-blocker administration in patients with COPD undergoing coronary artery bypass grafting. METHODS A total of 388 consecutive patients with COPD who underwent isolated coronary artery bypass grafting were studied, and clinical follow-up was completed. Diagnosis of COPD was based on preoperative forced expiration volume; exacerbation episodes were defined as a pulsed-dose prescription of prednisolone or a hospital admission for an exacerbation. Two propensity-matched cohorts of 104 patients each either receiving or not receiving β-blockers were identified. RESULTS At baseline, there was no significant difference among groups. After a median follow-up of 36 months, there were 8 deaths in 104 patients (7.7%) receiving β-blockers versus 19 deaths in 104 patients (18.3%) who did not receive β-blockers (p = 0.03). Kaplan-Meyer analysis showed a survival of 91.8% ± 2.8% for patients taking β-blockers versus 80.6% ± 4.0% for control subjects (χ(2), 29.4; p = 0.003; hazard ratio, 0.38). In addition, β-blocker administration did not increase rates of COPD exacerbation, which was experienced by 46 of 104 patients (44.2%) receiving β-blockers versus 45 of 104 patients (43.3%) not receiving β-blockers (p = 0.99). CONCLUSIONS This study showed that in patients with COPD undergoing coronary artery bypass grafting the administration of β-blockers is safe and significantly improves survival at mid-term follow-up. Further randomized studies are needed to confirm these findings.

Statins Improve Outcome in Isolated Heart Valve Operations: A Propensity Score Analysis of 3,217 Patients

BACKGROUND Whether statins can improve postoperative outcome in patients without coronary artery disease undergoing heart valve operations was assessed. METHODS Data for 3,217 patients undergoing isolated valve procedures at 2 institutions between May 2003 and May 2009 were reviewed. Clinical follow-up was completed. Two propensity-matched cohorts of 1,104 patients each were identified. Multivariable regression and Kaplan-Meyer survival analysis were performed to investigate risk factors correlated with death, stroke, myocardial infarction, and cardiac arrhythmias. RESULTS The overall 30-day mortality rate was 2.7%, and 2,096 of 2,149 hospital survivors were alive at a median follow-up of 27 months. Preoperative statin treatment was independently associated with a significant reduction in the risk of hospital death (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.32 to 0.89; p=0.001), postoperative cardiac arrhythmias (OR, 0.76; 95% CI, 0.62 to 0.93; p<0.006), and stroke (OR, 0.54; 95% CI, 0.32 to 0.92; p=0.02) but was not independently associated with a reduced risk of postoperative myocardial infarction. At follow-up, Kaplan-Meyer survival analysis showed statistically significant lower rates of mortality (χ2, 4.41; hazard ratio [HR], 1.59; 95% CI, 1.13 to 2.27; p=0.03), stroke (χ2, 11.42; HR, 2.15; 95% CI, 1.37 to 3.27; p=0.0007), cardiac arrhythmias (χ2, 19.9; HR, 2.13; 95% CI, 1.81 to 2.72; p<0.0001), and major adverse cardiac and cerebrovascular events (χ2, 3.74; HR, 1.37; 95% CI, 0.99 to 1.74; p=0.05) in patients receiving statin treatment. No statistically significant difference was found between groups in myocardial infarction incidence at follow-up. CONCLUSIONS Statin therapy is associated with a lower rate of adverse cardiovascular events after isolated heart valve operations.