Michael R. Petracek

The St Jude Medical Trifecta aortic pericardial valve: Results from a global, multicenter, prospective clinical study

BACKGROUND The St Jude Medical Inc (St Paul, Minn) Trifecta valve is a novel aortic biological prosthesis that incorporates several design features, including a true supra-annular sewing cuff, a stent design that maximizes valve hemodynamics while minimizing leaflet stresses, and an ethanol-based anticalcification technology. This study establishes the safety and early clinical and hemodynamic performance of the Trifecta valve. METHODS The Trifecta bioprosthesis was implanted in 1014 eligible patients between 2007 and 2009 at 31 centers. The mean age of the population was 72.5 ± 9.0 years, of whom 650 (64.1%) were male and 364 (35.9%) were female. Eighty-two subjects (8.1%) had undergone previous open surgery. Indications for aortic valve replacement surgery included stenosis in 556 patients (54.8%), regurgitation in 61 patients (6.0%), and mixed pathology in 397 patients (39.2%). RESULTS The overall follow-up included 844.3 late patient-years. Early (≤ 30 day) mortality occurred in 18 patients (1.8%), and there were 23 late (≥ 31 days) deaths yielding a linearized mortality rate of 2.72% per late patient-year. There were 27 early thromboembolic events, including 8 (0.8%) strokes, 17 (1.7%) reversible neurologic events, and 2 (0.2%) systemic embolic events. There were no instances of early valve thrombosis, endocarditis, or clinically significant hemolysis. There were 16 late thromboembolic events (linearized rate of 1.90% per year of follow-up), including 4 strokes and 12 reversible neurologic events. In total, there were 5 late valve explants, including 1 structural deterioration and 4 prosthetic valve endocarditis cases. Overall, freedom from valve explant was 99.4% at 2 years. At the time of discharge, average mean gradients ranged from 9.3 to 4.1 mm Hg and effective orifice area ranged from 1.58 to 2.50 cm(2) for valve sizes 19 to 29 mm, respectively. CONCLUSIONS The St Jude Medical Trifecta valve is a unique pericardial bioprosthesis with design elements that provide excellent hemodynamic performance while providing ease of implantation. Long-term follow-up continues to confirm the promising results of this innovative bioprosthesis.

High-Dose Perioperative Atorvastatin and Acute Kidney Injury Following Cardiac Surgery: A Randomized Clinical Trial

IMPORTANCE Statins affect several mechanisms underlying acute kidney injury (AKI). OBJECTIVE To test the hypothesis that short-term high-dose perioperative atorvastatin would reduce AKI following cardiac surgery. DESIGN, SETTING, AND PARTICIPANTS Double-blinded, placebo-controlled, randomized clinical trial of adult cardiac surgery patients conducted from November 2009 to October 2014 at Vanderbilt University Medical Center. INTERVENTIONS Patients naive to statin treatment (n = 199) were randomly assigned 80 mg of atorvastatin the day before surgery, 40 mg of atorvastatin the morning of surgery, and 40 mg of atorvastatin daily following surgery (n = 102) or matching placebo (n = 97). Patients already taking a statin prior to study enrollment (n = 416) continued taking the preenrollment statin until the day of surgery, were randomly assigned 80 mg of atorvastatin the morning of surgery and 40 mg of atorvastatin the morning after (n = 206) or matching placebo (n = 210), and resumed taking the previously prescribed statin on postoperative day 2. MAIN OUTCOMES AND MEASURES Acute kidney injury defined as an increase of 0.3 mg/dL in serum creatinine concentration within 48 hours of surgery (Acute Kidney Injury Network criteria). RESULTS The data and safety monitoring board recommended stopping the group naive to statin treatment due to increased AKI among these participants with chronic kidney disease (estimated glomerular filtration rate <60 mL/min/1.73 m2) receiving atorvastatin. The board later recommended stopping for futility after 615 participants (median age, 67 years; 188 [30.6%] were women; 202 [32.8%] had diabetes) completed the study. Among all participants (n = 615), AKI occurred in 64 of 308 (20.8%) in the atorvastatin group vs 60 of 307 (19.5%) in the placebo group (relative risk [RR], 1.06 [95% CI, 0.78 to 1.46]; P = .75). Among patients naive to statin treatment (n = 199), AKI occurred in 22 of 102 (21.6%) in the atorvastatin group vs 13 of 97 (13.4%) in the placebo group (RR, 1.61 [0.86 to 3.01]; P = .15) and serum creatinine concentration increased by a median of 0.11 mg/dL (10th-90th percentile, -0.11 to 0.56 mg/dL) in the atorvastatin group vs by a median of 0.05 mg/dL (10th-90th percentile, -0.12 to 0.33 mg/dL) in the placebo group (mean difference, 0.08 mg/dL [95% CI, 0.01 to 0.15 mg/dL]; P = .007). Among patients already taking a statin (n = 416), AKI occurred in 42 of 206 (20.4%) in the atorvastatin group vs 47 of 210 (22.4%) in the placebo group (RR, 0.91 [0.63 to 1.32]; P = .63). CONCLUSIONS AND RELEVANCE Among patients undergoing cardiac surgery, high-dose perioperative atorvastatin treatment compared with placebo did not reduce the risk of AKI overall, among patients naive to treatment with statins, or in patients already taking a statin. These results do not support the initiation of statin therapy to prevent AKI following cardiac surgery. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00791648.

Videothoracoscopy improved technique and expanded indications

Current videoendoscopic technology and percutaneous techniques of exposure and dissection have been successfully applied to abdominal surgery with favorable results. Application of this technology to our practice of thoracoscopy is the basis of this report. Videothoracoscopy has been performed in 39 patients for the following indications: chronic pleural effusion, interstitial lung disease, mediastinal lymphadenopathy in lung cancer, persistent air leak after decortication, mediastinal mass, recurrent spontaneous pneumothorax, hydropneumothorax with persistent air leak, and pleural-based mass. The technique we employ includes lateral decubitus positioning and double-lumen endotracheal intubation with ipsilateral lung collapse. The videoscope, retractors, and instruments are introduced through separate 10-mm incisions. Percutaneous manipulation of instruments and the videoscope is guided by images produced on television screens without dissection, and if resection is performed, the incision is enlarged to allow specimen retrieval. Procedures performed using this technique include pleural biopsy, partial pleurectomy, lysis of adhesions, lung biopsies, staging lymph node biopsy, lung nodule biopsy, pleural-based mass resection, and mediastinal mass biopsy and resection. This videoendoscopic technique greatly improves visualization of thoracic anatomy, facilitating thoracoscopy and enhancing exploration of the chest. It is preferred over conventional thoracoscopy and, in some patients, reduces the magnitude of operation by avoiding thoracotomy.

Internal Mammary Artery Grafts: Technical Factors Influencing Patency

Eight hundred fourteen patients with internal mammary artery (IMA) coronary artery bypass grafts have been restudied 961 times with coronary arteriography, primarily to evaluate the patency of the grafts in the setting of symptomatic coronary occlusive disease. Their records were reviewed to assess graft patency as related to the technical aspects of coronary artery bypass surgery. Patency was evaluated using life-table analysis of the data. The method of harvesting the IMA played no role in patency. The left anterior descending coronary artery was the recipient coronary artery with the highest patency rate. The left IMA had a significantly higher patency rate than the right IMA. As a group, the IMAs had a significantly higher patency rate than saphenous vein grafts. However, there was no difference between right IMA grafts and saphenous vein grafts. The mammary artery grafts that remained patent throughout the study had a significantly higher blood flow after bypass than did those that became occluded (43.0 +/- 0.9 versus 28.9 +/- 1.8 ml/min; p less than .001).

Milrinone Use Is Associated With Postoperative Atrial Fibrillation After Cardiac Surgery

Background— Postoperative atrial fibrillation (AF), a frequent complication after cardiac surgery, causes morbidity and prolongs hospitalization. Inotropic drugs are commonly used perioperatively to support ventricular function. This study tested the hypothesis that the use of inotropic drugs is associated with postoperative AF. Methods and Results— We evaluated perioperative risk factors in 232 patients who underwent elective cardiac surgery. All patients were in sinus rhythm at surgery. Sixty-seven patients (28.9%) developed AF a mean of 2.9±2.1 days after surgery. Patients who developed AF stayed in the hospital longer (P<0.001) and were more likely to die (P=0.02). Milrinone use was associated with an increased risk of postoperative AF (58.2% versus 26.1% in nonusers; P<0.001). Older age (63.4±10.7 versus 56.7±12.3 years; P<0.001), hypertension (P=0.04), lower preoperative ejection fraction (P=0.03), mitral valve surgery (P=0.02), right ventricular dysfunction (P=0.03), and higher mean pulmonary artery pressure (27.1±9.3 versus 21.8±7.5 mm Hg; P=0.001) also were associated with postoperative AF. In multivariable logistic regression, age (P<0.001), ejection fraction (P=0.02), and milrinone use (odds ratio, 4.86; 95% confidence interval, 2.31 to 10.25; P<0.001) independently predicted postoperative AF. When only data from patients with pulmonary artery catheters were analyzed and pulmonary artery pressure was included in the model, age, milrinone use (odds ratio, 4.45; 95% confidence interval, 2.01 to 9.84; P<0.001), and higher pulmonary artery pressure (P=0.02) were associated with an increased risk of postoperative AF. Adding other potential confounders or stratifying analysis by mitral valve surgery did not change the association of milrinone use with postoperative AF. Conclusion— Milrinone use is an independent risk factor for postoperative AF after elective cardiac surgery.

Internal Mammary Artery Graft at Reoperation: Risks, Benefits, and Methods of Preservation

To determine the effect of a prior internal mammary artery (IMA) graft on coronary artery bypass reoperation (CABR), we reviewed our experience with 410 consecutive patients: 313 received only saphenous vein grafts at initial coronary artery bypass grafting (CABG), and 97 received at least one IMA graft at CABG. Cardiac catheterization data before CABG were available in 110 patients (56 received only saphenous vein grafts, 54 received at least one IMA graft), allowing comparison of left ventricular function at CABG and CABR. Injury of the IMA graft occurred in 5 patients (1 death), but presence of an IMA graft was not an independent predictor of morbidity or mortality. Overall, the incidences of complications and deaths were higher in patients with saphenous vein grafts than in patients with IMA grafts, though not significantly so. Internal mammary artery grafts better preserved cardiac function: patients with IMA grafts had worse left ventricular function before CABG but better left ventricular function before CABR than patients with saphenous vein grafts. Left ventricular function deterioration from before CABG to before CABR was significantly less in patients with IMA grafts. We conclude that the risk of CABR is not increased by a previously constructed IMA graft and that left ventricular function is better preserved at CABR when an IMA graft was constructed at the initial operation.

Angiotensin-converting enzyme inhibition or mineralocorticoid receptor blockade do not affect prevalence of atrial fibrillation in patients undergoing cardiac surgery.

Objective: This study tested the hypothesis that interruption of the renin–angiotensin system with either an angiotensin-converting enzyme inhibitor or a mineralocorticoid receptor antagonist will decrease the prevalence of atrial fibrillation after cardiac surgery. Design: Randomized double-blind placebo-controlled study. Setting: University-affiliated hospitals. Patients: Four hundred forty-five adult patients in normal sinus rhythm undergoing elective cardiac surgery. Interventions: One week to 4 days prior to surgery, patients were randomized to treatment with placebo, ramipril (2.5mg the first 3 days followed by 5mg/day, with the dose reduced to 2.5mg/day on the first postoperative day only), or spironolactone (25mg/day). Measurements: The primary endpoint was the occurrence of electrocardiographically confirmed postoperative atrial fibrillation. Secondary endpoints included acute renal failure, hyperkalemia, the prevalence of hypotension, length of hospital stay, stroke, and death. Main Results: The prevalence of atrial fibrillation was 27.2% in the placebo group, 27.8% in the ramipril group, and 25.9% in the spironolactone group (p = .95). Patients in the ramipril (0.7%) or spironolactone (0.7%) group were less likely to develop acute renal failure than those randomized to placebo (5.4%, p = .006). Patients in the placebo group tended to be hospitalized longer than those in the ramipril or spironolactone group (6.8±8.2 days vs. 5.7±3.2 days and 5.8±3.4 days, respectively, p = .08 for the comparison of placebo vs. the active treatment groups using log-rank test). Compared with patients in the placebo group, patients in the spironolactone group were extubated sooner after surgery (576.4±761.5 mins vs. 1091.3±3067.3 mins, p = .04). Conclusions: Neither angiotensin-converting enzyme inhibition nor mineralocorticoid receptor blockade decreased the primary outcome of postoperative atrial fibrillation. Treatment with an angiotensin-converting enzyme inhibitor or mineralocorticoid receptor antagonist was associated with decreased acute renal failure. Spironolactone use was also associated with a shorter duration of mechanical ventilation after surgery.

Heme Oxygenase-1 and Acute Kidney Injury following Cardiac Surgery

Background: Intraoperative hemolysis and inflammation are associated with acute kidney injury (AKI) following cardiac surgery. Plasma-free hemoglobin induces heme oxygenase-1 (HO-1) expression. HO-1 degrades heme but increases in experimental models of AKI. This study tested the hypothesis that plasma HO-1 concentrations are associated with intraoperative hemolysis and are increased in patients that develop AKI following cardiac surgery. Methods: We measured plasma HO-1, free hemoglobin, and inflammatory markers in 74 patients undergoing cardiopulmonary bypass (CPB). AKI was defined as an increase in serum creatinine concentration of 50% or 0.3 mg/dl within 72 h of surgery. Results: Twenty-eight percent of patients developed AKI. HO-1 concentrations increased from 4.2 ± 0.2 ng/ml at baseline to 6.6 ± 0.5 ng/ml on postoperative day (POD) 1 (p < 0.001). POD1 HO-1 concentrations were 3.1 ng/ml higher (95% CI 1.1-5.1) in AKI patients, as was the change in HO-1 from baseline to POD1 (4.4 ± 1.3 ng/ml in AKI patients vs. 1.5 ± 0.3 ng/ml in no-AKI patients, p = 0.006). HO-1 concentrations remained elevated in AKI patients even after controlling for AKI risk factors and preoperative drug therapy. Peak-free hemoglobin concentrations correlated with peak HO-1 concentrations on POD1 in patients that developed AKI (p = 0.02). Duration of CPB and post-CPB IL-6 and IL-10 concentrations were also associated with increased HO-1 on POD1. Conclusion: Plasma HO-1 is increased in patients that develop AKI, and CPB duration, hemolysis, and inflammation are associated with increased HO-1 concentrations following cardiac surgery. Strategies that alter hemolysis and HO-1 expression during cardiac surgery may affect risk for AKI.

Minimally invasive mitral valve surgery expands the surgical options for high-risks patients.

Background:A simplified minimally invasive mitral valve surgery (MIMVS) approach avoiding cross-clamping and cardioplegic myocardial arrest using a small (5 cm) right antero-lateral incision was developed. We hypothesized that, in high-risk patients and in patients with prior sternotomy, this approach would yield superior results compared to those predicted by the Society of Thoracic Surgeons (STS) algorithm for standard median sternotomy mitral valve surgery. Methods:Five hundred and four consecutive patients (249 males/255 females), median age 65 years (range 20–92 years) underwent MIMVS between 1/06 and 8/09. Median preoperative New York Heart Association function class was 3 (range 1–4). Eighty-two (16%) patients had an ejection fraction ⩽35%. Forty-seven (9%) had a STS predicted mortality ≥10%. Under cold fibrillatory arrest (median temperature 28°C) without aortic cross-clamp, mitral valve repair (224/504, 44%) or replacement (280/504, 56%) was performed. Results:Thirty-day mortality for the entire cohort was 2.2% (11/504). In patients with a STS predicted mortality ≥ 10% (range 10%–67%), the observed 30-day mortality was 4% (2/47), lower than the mean STS predicted mortality of 20%. Morbidity in this high-risk group was equally low: 1 of 47 (2%) patients underwent reexploration for bleeding, 1 of 47 (2%) patients suffered a permanent neurologic deficit, none had wound infection. The median length of stay was 8 days (range 1–68 days). Conclusions:This study demonstrates that MIMVS without aortic cross-clamp is reproducible with low mortality and morbidity rates. This approach expands the surgical options for high-risk patients and yields to superior results than the conventional median sternotomy approach.

Midterm, multicenter clinical and hemodynamic results for the Trifecta aortic pericardial valve

Objective: To evaluate the midterm hemodynamic performance and clinical outcomes of the Trifecta aortic pericardial valve. Methods: In a multicenter, prospective, nonrandomized, follow‐up study, 710 patients underwent surgical implantation of a pericardial stented aortic prosthesis (Trifecta valve; St Jude Medical, St. Paul, Minn). The valve is constructed from bovine pericardium mounted externally onto a titanium stent. Subjects were followed on an annual basis over 6 years. Results: Operations were performed from 2007 to 2009, and mean age was 72.4 ± 9.3 years; 471 of 710 (66.3%) were men. Preoperatively, 361 of 710 (50.8%) of patients were in New York Heart Association class III or IV, and at 6 years postoperatively, 92 of 96 (95.8%) were New York Heart Association class I or II. Six years postoperatively, average mean gradient across all valve sizes was 11.0 mm Hg, and the average effective orifice area index was 0.80 cm2/m2. The proportion of patients without moderate‐to‐severe valvular regurgitation at 6 years was 95.2% (80/84). Six years postoperatively, freedom from valve‐related mortality, nonstructural dysfunction, and paravalvular leak were 98.3%, 98.6%, and 98.9%, respectively, and freedom from reoperation due to structural valve deterioration was 97.3% (95% confidence limits, 98.6‐94.7). Conclusion: These midterm results demonstrate that the Trifecta valve is a safe and effective valve substitute with excellent hemodynamic performance and durability that is maintained through the 6‐year follow‐up period.