Predicting adverse outcomes in elective coronary artery bypass graft surgery using pre-operative troponin I levels.

BACKGROUND: Cardiac troponins are frequently measured as part of the pre-operative work-up of patients prior to coronary artery bypass graft surgery (CABG). The utility of measuring these levels in elective patients, and the clinical implication of an abnormal result are unclear. The following study investigates the relationship between cardiac troponin I (cTnI) measured as part of a routine pre-operative work-up and outcomes following CABG. METHODS: From January 2010 to December 2012, 378 patients underwent isolated, elective CABG and had cTnI measured prospectively, as part of their pre-operative work-up. Patients were divided into normal (Group I) and elevated (Group II) cTnI groups. Pre-operative, operative and post-operative data were obtained from our institution's prospectively collected database. RESULTS: Elevated cTnI was present in 47 patients (12.4%) pre-operatively. Intra-operative variables did not differ between the elevated cTnI and control groups. Both 30-day mortality (Group I: 0.9% v Group II: 6.4%, p=0.03) and cardiac arrest (Group I: 1.5% v Group II: 8.5%, p=0.01) were significantly more frequent in the elevated cTnI group. In multivariable analysis, elevated cTnI remained a predictor for cardiac arrest (OR 5.8, 95% CI 1.2 - 29.2). CONCLUSIONS: Patients presenting for elective CABG frequently have elevated cTnI on pre-operative work-up. These patients may be at a greater risk of 30-day mortality and cardiac arrest. Routine pre-operative measurement of cTnI may alert clinicians to a higher operative risk.

Hybrid proximal surgery plus adjunctive retrograde endovascular repair in acute DeBakey type I dissection: superior outcomes to conventional surgical repair.

OBJECTIVE: The present study compared the outcomes between conventional surgery and the hybrid approach of proximal surgery with adjunctive retrograde descending aortic endografting plus distal bare metal stenting in acute DeBakey type I dissection. METHODS: From 2003 to 2011, 61 patients underwent surgical management for acute type A aortic dissection at our institution. Of these, 37 were DeBakey type I dissections: 18 patients (group 1) received conventional surgical repair alone, and 19 (group 2) underwent conventional hybrid surgery with adjunctive retrograde descending aortic stent grafting plus distal bare metal stenting. RESULTS: The patients' baseline characteristics were comparable, including the incidence of preoperative malperfusion syndromes (P = .23). The intraoperative and postoperative characteristics were similar, except 4 (22%) patients in group 1 (vs 0 in group 2) had ongoing malperfusion postoperatively (P = .04). Overall, hospital mortality was 11% (n = 2) for group 1 versus 5% (n = 1) for group 2. At a mean follow-up of 50 months, 4 (25%) subjects in group 1 required secondary thoracoabdominal aortic reintervention versus none in group 2 (P = .03). CONCLUSIONS: The use of adjunctive retrograde descending aortic endografting plus distal bare metal stenting during acute DeBakey type 1 dissection repair is a feasible method to enhance thoracoabdominal remodeling. This hybrid strategy improves perioperative outcomes and decreases late distal aortic complications compared with conventional surgical repair for acute DeBakey type I dissection. A prospective, multicenter study is warranted to definitively assess this promising new treatment paradigm.

Combined proximal stent grafting plus distal bare metal stenting for management of aortic dissection: Superior to standard endovascular repair?

OBJECTIVES: The present study compared the outcomes between combined proximal descending aortic endografting plus distal bare metal stenting and conventional proximal descending aortic stent-graft repair in patients with type A and type B aortic dissection. METHODS: From January 2003 to December 2010, 63 patients underwent endovascular treatment for acute (type A, 24; type B, 21) and chronic (type B, 18) aortic dissection. Of these, 40 patients underwent proximal descending aortic endografting plus distal bare metal stenting (group 1), and 23 underwent proximal descending stent-graft repair alone (group 2). All patients with type A dissection underwent open surgical intervention plus adjunctive retrograde endovascular repair. RESULTS: The patients were comparable for baseline characteristics and treatment indicators, but more group 1 patients were active smokers (P = .03). The intraoperative characteristics were also similar, although 4 patients, all in group 2, developed malperfusion syndrome postoperatively (P = .02). The overall hospital mortality was 6%. At a mean follow-up of 49 months, 9 group 2 patients (43%) required unplanned secondary intervention compared with 4 in group 1 (11%; P = .007). Reintervention for thoracoabdominal aortic aneurysm or visceral ischemia was performed in 4 patients (19%) from group 2 (P = .03). Late aortic-related deaths occurred in 1 (5 %) and 2 (5%) patients in groups 1 and 2, respectively. CONCLUSIONS: Combined proximal descending aortic endografting plus distal bare metal stenting for aortic dissection provides favorable short-term outcomes and decreases late distal aortic complications compared with conventional endovascular repair. These results support a more widespread application of this approach. A prospective, randomized trial is needed before definite conclusions can be made.

High incidence of insulin resistance and dysglycemia amongst nondiabetic cardiac surgical patients.

BACKGROUND: Undiagnosed glycometabolic dysfunction is prominent amongst nondiabetic cardiac surgical patients, whereas perioperative dysglycemia is associated with adverse outcomes. This study assessed whether the preoperative level of insulin resistance predicts the degree of perioperative dysglycemia in nondiabetic, normoglycemic cardiac surgical patients. METHODS: Twenty-two nondiabetic patients awaiting cardiac operations were assessed for metabolic parameters and whole-body insulin resistance (mean glucose infusion [GINF] rate) using the hyperinsulinemic-euglycemic clamp. Intraoperative and postoperative glucose levels and treatment requirements were analyzed. Linear regression analysis was used to find predictors of baseline, peak intraoperative, and mean postoperative fasting blood glucose (FBG). RESULTS: The mean GINF recorded in nondiabetic, normoglycemic patients was 3.5 ± 1.4 mg/kg/min. The mean peak intraoperative and mean postoperative FBG concentrations were 154.9 ± 34.2 mg/dL (range, 108.1 to 227.0 mg/dL) and 120.7 ± 16.2 mg/dL (range, 100.9 to 154.9 mg/dL), respectively. The GINF correlated inversely with mean peak intraoperative (r = -0.7, p = 0.02) and mean postoperative FBG (r = -0.8, p = 0.01). The GINF did not correlate with preoperative FBG levels (r = 0.3, p = 0.4). Preoperative FBG did not correlate with peak intraoperative (r = 0.4, p = 0.5) or mean postoperative FBG (r = 0.5, p = 0.3). CONCLUSIONS: Nondiabetic, normoglycemic cardiac surgical patients are highly insulin resistant using the hyperinsulinemic-euglycemic clamp. Preoperative insulin resistance, not FBG, is significantly associated with the development of perioperative dysglycemia. Insulin resistance screening may be useful to identify insulin resistance preoperatively and predict the degree of perioperative dysglycemia in cardiac surgical patients but should be performed with a more appropriate and reproducible test.

Combined proximal endografting with distal bare-metal stenting for management of aortic dissection.

BACKGROUND: Established endovascular treatments for aortic dissection often result in incomplete aortic repair, potentially leading to late complications involving the distal aorta. To address the problems of incomplete true lumen reconstitution and late aneurysmal change, we report the midterm results of combined proximal endografting with distal true lumen bare-metal stenting (STABLE: Staged Total Aortic and Branch vesseL Endovascular reconstruction) in Stanford type A and B aortic dissection. METHODS: Between January 2003 and January 2010, 31 patients underwent staged total aortic and branch vessel endovascular reconstruction for management of acute (type A, 13; type B, 11) and chronic (type B, 7) aortic dissection. Proximal endografting was combined with bare-metal Z stent implantation in the distal true lumen. Patients with type A dissection underwent adjunctive treatment at operation. Computed tomography angiography was performed at baseline, 1 year, and annually thereafter to assess aortic remodelling. RESULTS: Primary technical success was 97%. Thirty-day rates of death, stroke, and permanent paraplegia/paresis were 3% (n=1), 0%, and 0%, respectively. Mean follow-up was 57.3 months (range, 5 to 100 months). Overall survival was 60% at 100 months. Aortic-specific survival was 93%. Four patients (13%) underwent device-related reintervention. One (3%) late aortic-related death occurred. Thoracic (p=0.64) and abdominal (p=0.14) aortic dimensions were stable. The true lumen index increased significantly at follow-up. CONCLUSIONS: Staged total aortic and branch vessel endovascular reconstruction is a feasible ancillary endovascular technique to address the problems of distal true lumen collapse, incomplete aortic remodelling, and late aneurysm formation in aortic dissection.

Pre-operative use of levosimendan in two patients with severe aortic stenosis and left ventricular dysfunction.

We describe two patients with severe aortic stenosis, coronary artery disease, severe left ventricular dysfunction and heart failure in which the calcium-sensitising agent, levosimendan was administered prior to aortic valve replacement and coronary artery bypass graft surgery. In both cases, drug infusion was well tolerated at the doses used, heart failure improved significantly prior to surgery and peri-operative management was relatively uncomplicated in cases that would traditionally be considered high risk. Further investigation of the use of levosimendan both for treating heart failure in the presence of severe aortic stenosis and as pre-operative therapy is warranted.