Acute and chronic thoracic aortic disease: surgical considerations.

Acute thoracic aortic aneurysm is one of the most life-threatening vascular disorders recognized to date. The majority of these aortic ruptures rapidly end in mortality, with 50% of patients suffering death before reaching the hospital. Thus, acute management through surgical intervention is often indicated, especially in cases of ascending aortic rupture. Physical examination is critical in making the diagnosis, as clinical signs and symptoms often vary depending on the location of the dissection. Clinicians should have a low threshold for including thoracic aortic dissection in their differential diagnosis, especially when a patient presents with acute onset chest or back pain. In this report, we discuss the different categories of aortic dissections and the current treatment modalities for each. These include endovascular aortic repair, which has become a viable treatment modality in certain cases of type B dissection. Offering a less invasive approach, the technique known as thoracic endovascular repair currently affords a treatment option to a patient population who would have otherwise been deemed non-surgical candidates. Hybrid thoracic endovascular aortic repair has also become a pertinent surgical technique, and successful outcomes have been demonstrated when it is employed to repair ascending aortic aneurysms. We also describe our Acute Aortic Treatment Center, a rapid multicentric triage system for the management of acute aortic pathologies, which has resulted in significant improvements in patient outcomes.

Factors influencing immediate and long-term results after button's technique.

BACKGROUND: Aim of this study was to evaluate the factors influencing immediate and long-term results in patients undergoing aortic root replacement with a composite graft. METHODS: Between January 1989 and February 1999, 105 patients (83 males, 22 females) who underwent Bentall technique were studied. Preoperative diagnosis was annulo-aortic ectasia in 54, aortic dissection in 27, atherosclerotic aneurysm in 21, and aortitis in 3 cases. Seventeen patients were affected by Marfan's syndrome. All cases, elective, urgent, and emergency were included. Button technique was performed and the associated surgical procedures were coronary artery bypass grafting in 21, total aortic arch replacement in 15, proximal hemi arch in 5, and mitral valve replacement in 5 cases. RESULTS: The overall hospital mortality rate was 7.6% (n=8). Univariate analysis using chi(2) and/or two-sample "t"-test showed that dissection, aortitis, aneurysm rupture into-pleura or pericardium, emergency status, redo, prolonged pump times and circulatory arrest, were predictors influencing in-hospital mortality. Coagulopathy, low cardiac output, stroke, perioperative myocardial infarction, surgical bleeding leading to reoperation, were significantly related to in-hospital mortality (by correlation analysis). A multivariate analysis showed that, emergency status (p=0.027), aortic dissection (p=0.029), perioperative myocardial infarction (p=0.0021), reoperation for bleeding (p=0.0023), and pump time >180 min (p=0.011), were significant. The actuarial survival rate at 10 years follow-up was 84.7%. There were 8 late deaths. The Kaplan-Meier showed significant differences when considering dissection vs non-dissection (p=0.018), but did not reach significance in Marfan vs non-Marfan groups (p=0.83). NYHA class IV (p=0.052), previous cardiac surgery procedure (p=0.041), concomitant CABG (p=0.021), total aortic arch reconstruction (p=0.001), and mitral valve replacement (p=0.016), were identified as significant by Log Rank test. CONCLUSIONS: The Bentall procedure for aortic root replacement is safe and durable; in hospital mortality in elective status it was 1.28%; early and long-term mortality higher in patients with acute dissection. Six late deaths were procedures related. Sixty-six patients (76.4%) were in NYHA I class at follow-up. The incidence of late outcomes, thromboembolism (1.03%), graft infection (2.06%), pseudoaneurysm (0%), reoperation in ascending aorta or aortic valve (3.1%), operations on the remaining aorta (6.7%), and hemorrhage due to anticoagulant therapy (1.03%), are very low.

Adenosine triphosphate-dependent potassium channel modulation and cardioplegia-induced protection of human atrial muscle in an in vitro model of myocardial stunning.

OBJECTIVES: Although adenosine triphosphate-dependent potassium channel openers have been shown to enhance cardioplegic protection in animal myocardium, there is a lack of data on human cardiac tissues. We aimed at determining, on human atrial muscle, whether adenosine triphosphate- dependent potassium channels are involved in protection caused by high-potassium cardioplegia and whether adenosine triphosphate-dependent potassium channel activation might improve cardioplegic protection in an in vitro model of myocardial stunning. METHODS: Human atrial trabeculae were obtained from adult patients undergoing cardiac operations. In an organ bath at 37 degrees C, the preparations were subjected to 60 minutes of hypoxia at a high stimulation rate either in Tyrode solution (control, n = 17) or in St Thomas' Hospital solution without additives (n = 6) or associated with 100 nmol/L bimakalim (n = 7) or 1 micromol/L glibenclamide (n = 7), followed by 60 minutes of reoxygenation and 15 minutes of positive inotropic stimulation with 1 micromol/L dobutamine. RESULTS: Atrial developed tension was reduced by hypoxia to 27% +/- 5% of baseline and incompletely recovered after reoxygenation to 38% +/- 7%, whereas dobutamine restored contractility to 74% +/- 7% of basal values. St Thomas' Hospital solution with or without bimakalim improved developed tension after reoxygenation and dobutamine (P <.0001 vs control), whereas glibenclamide inhibited these protective effects of cardioplegic arrest (P =.001 vs St Thomas' Hospital solution). After reoxygenation, the protective effect of bimakalim disappeared at a high pacing rate (400- and 300-ms cycle length) but recovered during dobutamine superfusion. CONCLUSIONS: Adenosine triphosphate-dependent potassium channels are likely involved in the cardioprotective effects of cardioplegia in human atrial trabeculae and adenosine triphosphate-dependent potassium channel activation with bimakalim used as an additive to cardioplegia enhanced protection.

Effects of bimakalim on human cardiac action potentials: comparison with guinea pig and nicorandil and use-dependent study.

Electrophysiologic effects of K(ATP) channel openers (KCOs) are rarely studied for tissue and species specificity, and use-dependent investigations in human tissues are lacking. We therefore investigated in vitro the concentration-dependent effects of the KCO bimakalim [from 10 nM to 10 microM, at 1,000 ms of cycle length (CL) and 37 degrees C] on human (atrium, n = 4, and ventricle, n = 6) and guinea pig (atrium, n = 7, and ventricle, n = 6) transmembrane action potential (AP). The frequency relation (from CL 1,600 to 300 ms, 31 degrees C) of human atrial AP duration 90% (APD90) shortening (10 microM vs. baseline, n = 7) also was determined. A parallel study was performed with the KCO nicorandil (from 10 nM to 1 mM, n = 3) in human atrial APs, at 31 degrees C. Resting membrane potential and maximal upstroke velocity of AP were not modified by bimakalim at maximal concentration, whereas AP amplitude was decreased in both guinea pig preparations (p < 0.05); APD90 was shortened in all tissues (p < 0.01). Median effective concentration (EC50) for APD90 shortening at 37 degrees C was 0.54 and 2.74 microM in atrial and ventricular human tissue, respectively, and 8.55 and 0.89 microM in atrial and ventricular guinea pig tissue, respectively. In human atrial tissue at 31 degrees C, EC50 with bimakalim was 0.39 microM; a much higher value was seen with nicorandil (210 microM). Bimakalim (10 microM)-induced APD90 shortening as a function of stimulation rate was greatest at longest CL. Evidence is provided for (a) species (human vs. guinea pig) and tissue (atrium vs. ventricle) differential AP sensitivity to bimakalim; (b) an approximately 500-fold higher efficacy of bimakalim versus nicorandil to shorten human atrial APD90; and (c) normal use-dependence of human atrial APD90 shortening with bimakalim at 10 microM.

Results of contemporary surgical treatment of descending thoracic aortic aneurysms: experience in 198 patients.

Between April 1987 and March 1995, 198 patients (133 males [67.17%] and 65 female [32.83%]; mean age 63.85 years) underwent descending thoracic aortic aneurysm repair. Of these, 142 patients (71.71%) had symptoms. In most patients (n = 123 [62%]) the aneurysmal disease was extensive, involving at least two thirds of the descending aorta. In 153 patients (77.27%), the repair was completed with the simple clamp technique (mean clamping time 24.6 minutes). Left atrium-to-femoral bypass was used in 26 patients (13.13%) at high risk (mean clamping time 37.4 minutes). Profound hypothermia and circulatory arrest were necessary in 19 patients (9.6%) with extensive aneurysms that involved the arch and ascending aorta (mean circulatory arrest time 46 minutes). Operative mortality was 5.1% (n = 10). The causes of death were cardiac in three patients (1.5%), pulmonary in four (2.0%), and renal in three (1.5%). Postoperative paraplegia occurred in three patients (1.5%). Important predictors (p < 0.05) of mortality at regression analysis included renal failure, pulmonary complications, and paraplegia. The only independent predictor of paraplegia was clamping time. In conclusion, the simple clamp procedure remains the technique of choice in the majority of patients with descending aortic aneurysms. Atriofemoral bypass is an important adjunct in patients at high risk.

Inhaled nitric oxide in patients with severe heart failure: changes in lung perfusion and ventilation detected using scintigraphy.

Inhaled nitric oxide (NO) is a selective pulmonary vasodilator in patients with end-stage cardiac failure. Preoperative high pulmonary vascular resistance could modify early and late results after heart transplantation generally due to right-ventricular failure. Aim of this study was to assess pulmonary vascular resistance variability following inhalation of NO by using a scintigraphic method. Our preliminary results suggest that inhaled NO in patients with end-stage heart failure redistributes blood away from apical regions and towards more basal and posterior segments, probably dilating blood vessels in ventilated but nonperfused zones. NO may represent a simple and reliable method to evaluate dynamic response of pulmonary vasculature.

Coronary artery revascularization followed by single-lung transplantation in a patient with combined end-stage idiopathic pulmonary fibrosis and left main coronary artery stenosis.

Single-lung transplantation has been used successfully in patients who have idiopathic pulmonary fibrosis; however, coronary artery disease is often considered a contraindication for lung transplantation in such patients. We report the case of a 53-year-old man with idiopathic pulmonary fibrosis in whom left main coronary artery stenosis was found incidentally during pretransplant evaluation. The patient was treated successfully with elective coronary artery bypass grafting, followed by left single-lung transplantation 35 days later.

Left thoracotomy for coronary revascularization after esophagoplasty with substernal colon interposition.

A 66-year-old man was referred to our institution with recurrent angina pectoris caused by 95% stenosis of the left anterior descending coronary artery. Twelve years earlier, he had undergone esophagoplasty with substernal colon interposition for an esophageal burn caused by a caustic substance. A left thoracotomy approach and femoro-femoral bypass were used safely for coronary artery revascularization.

Concomitant cardiac and pulmonary operations for lung cancer.

From 1973 through 1990, 21 patients (17 men and 4 women) underwent concomitant cardiac operation and pulmonary resection for lung cancer. The mean age was 65.3 years (range, 50 to 80 years). Eighteen patients underwent coronary artery bypass; 1 underwent coronary bypass and mitral valve replacement; 1, aortic valve replacement; and 1, left ventricular aneurysmectomy. Pulmonary procedures included 16 lobectomies, 3 segmentectomies, and 2 wedge resections. Nine resections were performed during cardiopulmonary bypass, and 12 were performed either before or after bypass. On final pathologic diagnosis, 11 patients had adenocarcinoma, 7 had squamous cell carcinoma, and 3 had undifferentiated lesions. Twelve patients were in cancer stage 1 and 9 were in stage II. Placement of an intraaortic balloon pump was required in 3 patients. No patient sustained excessive blood loss requiring reoperation. Only 2 incidents (9.5%) of disseminated infection were reported. The overall 1-year survival rate was 90.5% and the 5-year survival rate was 52.4%. We found concomitant cardiac operation and pulmonary resection for lung cancer to be a safe and effective alternative to staged treatment in patients not requiring a pneumonectomy. Combined cardiac and pulmonary surgery spares the patient the risk and cost of a 2nd major surgical procedure without compromising long-term survival.