Richard C. Daly

Congenitally bicuspid aortic valves: a surgical pathology study of 542 cases (1991 through 1996) and a literature review of 2,715 additional cases.

OBJECTIVE To describe a clinicopathologic study of a large group of congenitally bicuspid aortic valves surgically excised at a single institution. MATERIAL AND METHODS The medical charts and bicuspid valves from patients undergoing aortic valve replacement at Mayo Clinic Rochester between 1991 and 1996 were retrospectively reviewed. RESULTS The age of the 542 patients ranged from 1 to 86 years (mean, 61), and 372 (69%) were men. Among these, 409 (75%) had pure aortic stenosis (AS), 73 (13%) had pure aortic insufficiency (regurgitation) (AI), 53 (10%) had combined AS and AI, and 7 (1%) had normal function. The mean age was higher for those with AS than AI (65 versus 46 years; P < 0.001), whereas the male-to-female ratio was higher for AI than AS (17.3:1 versus 1.7:1; P < 0.001). The two cusps were not equal in size in 95%, and a raphe was present in 76% (67% typical, 9% atypical). Raphal position was described in 315 and was between the right and left cusps in 270 (86%). Raphal absence occurred more often in valves with equal-sized cusps than unequal (33% versus 14%; P = 0.005). Moderate to severe calcification affected valves with AS more frequently than AI (99% versus 41%; P < 0.001). In contrast, annular dilatation was associated with AI more than AS (48% versus 11%; P < 0.001). Acquired commissural fusion involved valves with combined AS and AI more often than the other functional states (31% versus 14%; P = 0.002). Sixteen patients (age range, 18 to 78 years; 13 men) had infective endocarditis (6 active, 10 healed), including 10 with AI (9 men), 3 with AS plus AI, 2 with AS, and 1 with normal function but embolization. CONCLUSION Functionally, the most common fate of congenitally bicuspid aortic valves was calcific stenosis with or without regurgitation (85%). Because approximately 4 million US citizens have bicuspid valves and because valve replacement is currently the only treatment of symptomatic AS, this disorder will continue to affect health-care costs.

Clinical accuracy of RIFLE and Acute Kidney Injury Network (AKIN) criteria for acute kidney injury in patients undergoing cardiac surgery

IntroductionThe RIFLE (risk, injury, failure, loss of kidney function, and end-stage renal failure) classification for acute kidney injury (AKI) was recently modified by the Acute Kidney Injury Network (AKIN). The two definition systems differ in several aspects, and it is not clearly determined which has the better clinical accuracy.MethodsIn a retrospective observational study we investigated 4,836 consecutive patients undergoing cardiac surgery with cardiopulmonary bypass from 2005 to 2007 at Mayo Clinic, Rochester, MN, USA. AKI was defined by RIFLE and AKIN criteria.ResultsSignificantly more patients were diagnosed as AKI by AKIN (26.3%) than by RIFLE (18.9%) criteria (P < 0.0001). Both definitions showed excellent association to outcome variables with worse outcome by increased severity of AKI (P < 0.001, all variables). Mortality was increased with an odds ratio (OR) of 4.5 (95% CI 3.6 to 5.6) for one class increase by RIFLE and an OR of 5.3 (95% CI 4.3 to 6.6) for one stage increase by AKIN. The multivariate model showed lower predictive ability of RIFLE for mortality. Patients classified as AKI in one but not in the other definition set were predominantly staged in the lowest AKI severity class (9.6% of patients in AKIN stage 1, 2.3% of patients in RIFLE class R). Potential misclassification of AKI is higher in AKIN, which is related to moving the 48-hour diagnostic window applied in AKIN criteria only. The greatest disagreement between both definition sets could be detected in patients with initial postoperative decrease of serum creatinine.ConclusionsModification of RIFLE by staging of all patients with acute renal replacement therapy (RRT) in the failure class F may improve predictive value. AKIN applied in patients undergoing cardiac surgery without correction of serum creatinine for fluid balance may lead to over-diagnosis of AKI (poor positive predictive value). Balancing limitations of both definition sets of AKI, we suggest application of the RIFLE criteria in patients undergoing cardiac surgery.

Surgery for aneurysms of the aortic root: A 30-year experience

Background—This study evaluated long-term results of aortic root replacement and valve-preserving aortic root reconstruction for patients with aneurysms involving the aortic root. Methods and Results—Two-hundred three patients aged 53±16 years (mean±SD; 153 male, 50 female) underwent elective or urgent aortic root surgery from 1971 to 2000 for an aortic root aneurysm: 149 patients underwent a composite valve conduit reconstruction, and 54 patients underwent valve-preserving aortic root reconstruction. Fifty patients had Marfan syndrome. In-hospital and 30-day mortality was 4.0% (8/203) overall: for a composite valve conduit procedure, the corresponding value was 4.0% (6/149) and for valve-preserving procedure, 3.7% (2/54) (P=NS). Morbidity included 3 strokes (1%), 10 perioperative myocardial infarctions (5%), and 8 reoperations for bleeding (4%). Actuarial survival at 5, 10, 15, and 20 years was 93% (95% confidence interval [CI] = 88% to 97%), 79% (95% CI = 71% to 87%), 67% (95% CI = 57% to 79%), and 52% (95% CI = 36% to 69%), respectively. Freedom from reoperation was 72% (95% CI = 54% to 86%) at 20 years. Complications with anticoagulation occurred in 29 patients; with valve thrombosis, in 2; and with hemorrhage, in 27 (4 life threatening and 23 minor). Freedom from thromboembolism was 91% (95% CI = 77% to 98%) at 20 years. Freedom from endocarditis was 99% (95% CI = 92% to 100%) at 20 years. Multivariate analysis revealed preoperative mitral valve regurgitation (+3 to 4) and older age to be significant predictors of late death (P≤0.005), and Marfan syndrome, initial valve-preserving aortic root reconstruction, and need for a concomitant procedure at initial operation to be significant predictors of the need for reoperation (P≤0.01). Conclusions—Aortic root replacement for aortic root aneurysms can be done with low morbidity and mortality. Composite valve conduit reconstruction resulted in a durable result. There were few serious complications related to the need for long-term anticoagulation or a prosthetic valve. Reoperation was most commonly required because of failure of the aortic valve when a valve-preserving aortic root reconstruction was performed or for other cardiac or aortic disease elsewhere.

Pulmonary resection of metastatic renal cell carcinoma

Between 1965 and 1989, 96 consecutive patients (64 men and 32 women) underwent complete pulmonary resection for metastatic renal cell carcinoma. Median age was 63 years (range, 33 to 82 years). Median time between nephrectomy and pulmonary resection was 3.4 years (range, 0 to 18.4 years). Forty-eight patients had solitary metastasis, 16 had two, 18 had three, and 14 had more than three. Wedge excision was performed in 62 patients, segmentectomy in 3, lobectomy in 25, bilobectomy in 3, and pneumonectomy in 3. Fourteen patients had repeat thoracotomy for recurrent metastasis; 34 other patients also had complete resection of limited extrapulmonary disease. There were no operative deaths. Median follow-up was 3 years (range, 70 days to 19.0 years). Overall 5-year survival was 35.9%. Patients with solitary metastasis had a 5-year survival of 45.6% compared with 27.0% for patients with multiple metastases (p < 0.05). Patients with a tumor-free interval greater than the median of 3.4 years had a better survival (p = 0.05) than those with a tumor-free interval less than or equal to 3.4 years. Five-year survival for patients who underwent repeat thoracotomy or had complete resection of extrapulmonary disease did not differ from overall survival. We conclude that resection of renal lung metastasis is safe and effective, that patients with solitary metastasis have a better survival than those with multiple metastases, that resectable extrapulmonary disease does not necessarily contra-indicate pulmonary resection, and that repeat thoracotomy is warranted in selected patients with recurrent lung metastases.

Readmissions after implantation of axial flow left ventricular assist device.

OBJECTIVES The purpose of this study was to determine the occurrence and causes of readmissions after implantation of axial flow left ventricular assist device (LVAD). BACKGROUND Based on the REMATCH (Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure) study experience, readmissions after LVAD implantation are thought to be frequent. METHODS We retrospectively analyzed admissions to our facility in a cohort of 115 patients implanted between January 2008 and July 2011 with the HeartMate II axial flow LVAD, of whom 42 were bridged to transplant. To account for repeated events, Andersen-Gill models were used to determine possible predictors. RESULTS The patients were followed for 1.4 ± 0.9 years. There were 224 readmissions in 83 patients. The overall readmission rate was 1.64 ± 1.97 per patient-year of follow-up. The readmission rate for the first 6 months was 2.0 ± 2.3 and decreased to 1.2 ± 2.1 during subsequent follow-up. Leading causes were bleeding (66 readmissions in 34 patients), mostly gastrointestinal bleed (51 in 27 patients), cardiac (51 in 36 patients, most for HF or arrhythmia), infections (32 in 25 patients) of which 6 were pump related, and thrombosis (20 in 15 patients) including 13 readmissions due to hemolysis. Preoperative variables associated with (fewer) readmissions in a multivariate model include residence within our hospital-extended referral zone of Minnesota and the neighboring states (hazard ratio: 0.66; 95% confidence interval: 0.48 to 0.91; p = 0.011), hemoglobin (hazard ratio: 0.91, 95% confidence interval: 0.84 to 0.99; p = 0.027) and N-terminal pro-B-type natriuretic peptide (hazard ratio: 0.98; 95% confidence interval: 0.96 to 1.0 per 1,000-unit increase, p = 0.022). C-statistic for the model: 0.63. CONCLUSIONS Readmission rates after axial flow LVAD implantation decrease during the first 6 months and then stabilize. The leading causes are bleeding, cardiac (heart failure and arrhythmia), infections, and thrombosis.

Epiphrenic diverticulum: Results of surgical treatment☆

From 1975 to 1991, 112 patients (64 men and 48 women) were found to have an epiphrenic diverticulum. Symptoms were absent or minimal in 71 patients and incapacitating in 41. All patients with minimal symptoms were managed conservatively; 35 were available for follow-up, which ranged from 1 to 25 years (median, 9 years). None of these 35 patients had clinically significant progression of symptoms. Surgical repair was done in 33 patients with incapacitating symptoms. Achalasia was present in 8 of the surgical patients (24.2%), diffuse esophageal spasm in 3 (9.1%), hypertensive lower esophageal sphincter alone in 1 (3.0%), and nonspecific motor abnormalities of the esophageal body in 7 (21.2%). Diverticulectomy and esophagomyotomy were performed in 22 patients, diverticulectomy alone in 7, esophageal resection in 3, and esophagomyotomy alone in 1. Concomitant hiatal hernia repair was done in 6 patients. Complications occurred in 11 patients; 6 had esophageal leaks. There were three operative deaths (9.1%), all occurring in patients with abnormal manometry. Follow-up was complete in 29 patients and ranged from 4 months to 15 years (median, 6.9 years). Long-term results were excellent in 14 patients (48.2%), good in 8 (27.6%), fair in 5 (17.2%), and poor in 2 (6.9%). We conclude that operation has significant risks and is not warranted in patients with minimal symptoms because progression is unlikely. Surgical treatment, however, is advisable in patients with incapacitating symptoms because most operative survivors will have long-term symptomatic palliation.

Multiple arterial grafts improve late survival of patients undergoing coronary artery bypass graft surgery: analysis of 8622 patients with multivessel disease.

Background— Use of the left internal mammary artery (LIMA) in multivessel coronary artery disease improves survival after coronary artery bypass graft surgery; however, the survival benefit of multiple arterial (MultArt) grafts is debated. Methods and Results— We reviewed 8622 Mayo Clinic patients who had isolated primary coronary artery bypass graft surgery for multivessel coronary artery disease from 1993 to 2009. Patients were stratified by number of arterial grafts into the LIMA plus saphenous veins (LIMA/SV) group (n=7435) or the MultArt group (n=1187). Propensity score analysis matched 1153 patients. Operative mortality was 0.8% (n=10) in the MultArt and 2.1% (n=154) in the LIMA/SV (P=0.005) group, which was not statistically different (P=0.996) in multivariate analysis or the propensity-matched analysis (P=0.818). Late survival was greater for MultArt versus LIMA/SV (10- and 15-year survival rates were 84% and 71% versus 61% and 36%, respectively [P<0.001], in unmatched groups and 83% and 70% versus 80% and 60%, respectively [P=0.0025], in matched groups). MultArt subgroups with bilateral internal mammary artery/SV (n=589) and bilateral internal mammary artery only (n=271) had improved 15-year survival (86% and 76%; 82% and 75% at 10 and 15 years [P<0.001]), and patients with bilateral internal mammary artery/radial artery (n=147) and LIMA/radial artery (n=169) had greater 10-year survival (84% and 78%; P<0.001) versus LIMA/SV. In multivariate analysis, MultArt grafts remained a strong independent predictor of survival (hazard ratio, 0.79; 95% confidence interval, 0.66–0.94; P=0.007). Conclusions— In patients undergoing isolated coronary artery bypass graft surgery with LIMA to left anterior descending artery, arterial grafting of the non–left anterior descending vessels conferred a survival advantage at 15 years compared with SV grafting. It is still unproven whether these results apply to higher-risk subgroups of patients.

Determinants of survival and recovery of left ventricular function after aortic valve replacement

To determine factors that influence survival and recovery of ventricular function in patients undergoing aortic valve replacement in the current surgical era, baseline risk factors related to outcome were analyzed in 1,012 consecutive patients undergoing aortic valve replacement between 1983 and 1990. Forty-two percent of patients underwent concomitant coronary bypass. Observed survival probabilities (expressed as 30-day/5-year) were 0.97/0.81 overall, 0.99/0.89 for patients aged less than 70 years, and 0.95/0.74 for patients aged 70 years or greater. Advanced age (p < 0.0001), decreased ejection fraction (p < 0.0001), extent of coronary disease (p < 0.006), smaller prosthetic valve (p < 0.03), and advanced New York Heart Association class (p < 0.04) were incremental risk factors for mortality. In patients with preoperative ventricular dysfunction (ejection fraction < or = 0.45), ejection fraction measured 1.4 years after aortic valve replacement improved in 72% and the mean increment in ejection fraction was 0.175 (95% confidence interval, 0.154 to 0.195). The increment in ejection fraction was greater in female patients than in male patients (p < 0.02) and greater in patients without than with coronary disease (p < 0.02). Female sex (p < 0.02) and lesser extent of coronary disease (p < 0.05) were independent predictors of change in ejection fraction. In all patients, early improvement in ejection fraction conveyed an independent subsequent survival benefit (p < 0.0001). The results of aortic valve replacement in the current era are excellent, and the majority of patients with ventricular dysfunction demonstrate significant improvement. Early improvement in ejection fraction, influenced by coexistent coronary artery disease and sex-associated factors, importantly affects subsequent survival.

Aortic valve replacement in patients aged eighty years and older: Early and long-term results

UNLABELLED We have studied 322 patients, 80 years of age or older, who underwent aortic valve replacement between June 1971 and December 1992. Two hundred six patients (64%) have had surgery since the end of 1985. Their mean age was 82.7 years (range 80 to 92 years). One hundred seventy-one (53%) were male and most (86%) were in New York Heart Association class III-IV. Fifty-seven patients (18%) required admission to the coronary care unit before the operation. One hundred seventy-nine patients (56%) underwent an urgent or emergency operation. Known cerebrovascular disease was present in 77 (24% of patients), aortic stenosis in 79%, aortic incompetence in 9%, and combined stenosis and incompetence in 12%. Associated procedures included bypass grafting in 139 (43%), mitral valve replacement/repair in 20 (6%), tricuspid valve repair in 6 (2%), and aortic annular enlargement in 38 (12%). Thirty patients (9.3%) were undergoing reoperation. Hospital mortality was 44 of 322 (13.7%). The median hospital stay was 11 days. On univariate analysis, significant predictors of hospital mortality were female sex, preoperative rest pain, New York Heart Association class III-IV, admission to the coronary care unit, heart failure, mitral valve disease, emergency/urgent operation, chronic obstructive pulmonary disease, bypass grafting, valve size, peripheral vascular disease, and ejection fraction less than 0.35. On multivariate analysis the most important independent predictors of operative mortality were female gender (p = 0.0001), renal impairment (p = 0.001), bypass grafting (p = 0.005), ejection fraction less than 0.35 (p = 0.01), and chronic obstructive pulmonary disease (p = 0.028). Age and year of operation did not influence mortality. Five-year survivals for all patients and for operative survivors were 60.2% +/- 3.2% and 70.3% +/- 3.4%, respectively. On univariate analysis, factors that adversely affected long-term survival were coronary bypass grafting (p = 0.007), more than two comorbidities (p = 0.02), male gender (p = 0.04), and ejection fraction less than 0.35 (p = 0.04). On multivariate analysis, no factor was consistently significant for long-term survival. At most recent clinical follow-up 85% were angina free and 82% were in class I-II. At least 92% of patients, both at 1 year and at most recent clinical follow-up, believed they had significantly benefited from the operation: CONCLUSION Risk factors for aortic valve replacement in octogenarians include female gender, unstable symptoms, poor ejection fraction, renal impairment, and bypass grafting. However, despite a hospital mortality higher than that reported for younger patients, the outlook for operative survivors is excellent, with good relief of symptoms and an expected survival normal for this particular age group. If possible, aortic valve replacement should be done before development of unstable symptoms.

The benefits of early valve replacement in asymptomatic patients with severe aortic stenosis

OBJECTIVE The prevalence of aortic valve stenosis increases with age, and often the diagnosis is made by echocardiography before symptoms develop. To address the controversies in management of asymptomatic patients with severe aortic stenosis, we assessed the early and late outcomes of aortic valve replacement in these patients. METHODS We analyzed data of 622 patients, aged 72 +/- 11 years, with isolated asymptomatic severe aortic stenosis. Patients were identified with a peak systolic velocity of greater than 4 m/s by transthoracic echocardiography and monitored for the development of symptoms and need for aortic valve replacement. RESULTS After the initial diagnosis, 166 (27%) patients who were initially asymptomatic experienced the development of chest pain, shortness of breath, or syncope and had aortic valve replacement at Mayo Clinic. Another 97 (16%) patients had aortic valve replacement in the absence of symptoms. Symptomatic patients were more likely to undergo coronary bypass grafting (P < .01) and have diabetes, hypercholesterolemia, and a lower ejection fraction (P < .05 for each). Operative mortality was 2% for symptomatic patients and 1% for asymptomatic patients (P = .43). The survival of the 263 patients who underwent aortic valve replacement was not significantly different from an age- and sex-matched population (P = .99); 10-year survival was 64% (95% confidence interval [CI] 57%-72%) for symptomatic patients and 64% (95% CI 54%-75%) for asymptomatic patients (P = .92). At 3 years after diagnosis of severe aortic stenosis, 52% (95% CI 48%-56%) of 622 patients had had symptoms develop, undergone aortic valve replacement, or died. Among the entire cohort, older age at diagnosis (hazard ratio [HR] 1.1 per year, P < .001), diabetes (HR 1.7, P < .001), decreased ejection fraction (HR 1.1 per 1% downward arrow, P = .01), symptoms (HR 2.13, P < .001), and absence of aortic valve replacement (HR 3.53, P < .001) were identified as independent risk factors for mortality. CONCLUSION Among patients with severe aortic stenosis who underwent aortic valve replacement, early and late outcomes were similarly good in patients who had symptoms before the operation compared with those who were asymptomatic. It is important to note that among patients with asymptomatic severe aortic stenosis, the omission of surgical treatment was the most important risk factor for late mortality.