Enio Buffolo

Coronary artery bypass grafting without cardiopulmonary bypass

BACKGROUND Coronary artery bypass grafting without cardiopulmonary bypass is now an accepted technique of myocardial revascularization. We herein report our total experience with this procedure. METHODS In a consecutive series of 8,751 patients operated on in our institution for coronary artery disease from 1981 to 1994, 1,274 patients received coronary artery bypass grafting without cardiopulmonary bypass. RESULTS Results indicate that the operation can be performed with an acceptable mortality (2.5%), and that all types of arterial conduits can be used. Most commonly the left anterior descending and right coronary arteries were bypassed. The incidence of arrhythmias and of pulmonary and neurologic complications were significantly lower in this group of patients compared with patients receiving coronary artery bypass grafting with cardiopulmonary bypass. Most importantly, there was decreased cost when the procedure was used because no extracorporeal circulation, cardioplegia sets, or other cannulas were used. CONCLUSIONS We conclude that the continuing use of coronary artery bypass grafting without cardiopulmonary bypass is justified and that, with proper selection of patients, the procedure is safe and cost-effective.

Randomized trial of direct coronary angioplasty versus intravenous streptokinase in acute myocardial infarction

OBJECTIVES The objective of this study was to obtain preliminary data on the relative clinical utility of direct coronary angioplasty compared with that of intravenous thrombolytic therapy for patients with acute myocardial infarction. BACKGROUND The relative merits of intravenous thrombolytic therapy and direct coronary angioplasty as treatment for acute myocardial infarction are incompletely understood, and randomized trials of these treatments have been extremely limited. METHODS One hundred patients with ST segment elevation presenting to a single high volume interventional center within 6 h of the onset of chest pain were randomized to receive either streptokinase (1.2 million U intravenously over 1 h) or immediate catheterization and direct coronary angioplasty. Patients were excluded for age > or = 75 years, prior bypass surgery, Q wave infarction in the region of ischemia or excessive risk of bleeding. All patients were then treated with aspirin (325 mg orally/day) and heparin (1,000 U intravenously/h) for 48 h until catheterization was performed to determine the primary study end point, namely, infarct-related artery patency at 48 h. Secondary end points were in-hospital death, left ventricular ejection fraction at 48 h and time to treatment. RESULTS There was no difference in the baseline characteristics of the two treatment groups. Overall patient age was 56 +/- 10 years, 83% of patients were male, 11% had prior infarction, 40% had anterior infarction and 97% were in Killip class I or II. Although time to treatment was delayed in the angioplasty group (238 +/- 112 vs. 179 +/- 98 min, p = 0.005), there was no difference in 48-h infarct-related artery patency or left ventricular ejection fraction (patency 74% vs. 80%; ejection fraction 59 +/- 13% vs. 57 +/- 13%; angioplasty vs. streptokinase, p = NS for both). There were no major bleeding events, and the mortality rate with angioplasty (6%) and streptokinase (2%) did not differ (p = NS). CONCLUSIONS These results suggest that intravenous thrombolytic therapy might be preferred over coronary angioplasty for most patients because of the often shorter time to treatment.

Inflammatory response after myocardial revascularization with or without cardiopulmonary bypass

BACKGROUND Tumor necrosis factor-alpha has been implicated in complications seen after cardiac operations with cardiopulmonary bypass. The release of tumor necrosis factor-alpha and its possible effects were studied in patients undergoing coronary artery bypass grafting with and without cardiopulmonary bypass. METHODS Twenty patients were studied, 10 with (group 1) and 10 without cardiopulmonary bypass (group 2). Serial blood samples were obtained before, during, and up to 48 hours after operation. Circulating tumor necrosis factor-alpha levels, leukocyte counts, and erythrocyte sedimentation rates were measured. Hemodynamic variables (blood pressure and heart rate), temperature, orotracheal intubation time, postoperative bleeding, and inotropic drug requirements were compared. RESULTS Serum levels of tumor necrosis factor-alpha were detected in 6 patients (60%) in group 1 and none in group 2. The patients in group 1 had more hypotension than those in group 2 (7.4 +/- 1.0 mm Hg versus 8.5 +/- 0.7 mm Hg), required more inotropic drugs (8 patients versus 1 patient), and had a higher heart rate (114 +/- 8 beats per minute versus 98 +/- 10 beats per minute), a higher temperature (37.1 degrees +/- 0.5 degrees C versus 36.6 degrees +/- 0.3 degrees C), increased postoperative bleeding (820 +/- 120 mL versus 360 +/- 84 mL), a longer orotracheal intubation time (13.6 +/- 2.2 hours versus 9.3 +/- 1.4 hours), and a more pronounced leukocytosis. CONCLUSIONS Cardiopulmonary bypass induces the whole-body inflammatory response through the release of tumor necrosis factor alpha, resulting in adverse systemic effects.

Off-pump versus on-pump myocardial revascularization in low-risk patients with one or two vessel disease: perioperative results in a multicenter randomized controlled trial

BACKGROUND To evaluate hospital mortality and morbidity after myocardial revascularization in a prospective and multicenter study, comparing on-pump versus off-pump in a special subset of patients with lesions in the left descending artery, alone or associated with the right coronary artery. METHODS A multicenter prospective randomized study was performed. One hundred and sixty selected low-risk patients were enrolled; 80 patients were operated on-pump (coronary artery bypass grafting [CABG], group I) and 80 patients were operated off-pump (off-pump coronary artery bypass [OPCAB], group II). One hundred and five were male and ages ranged from 39 to 70 years old; mean 58.81 +/- 9.31 and median 59. Preoperative clinical characteristics were similar in both groups; only previous myocardial infarction was higher in the OPCAB group. Patients with severe left ventricular dysfunction (FE </= 35%), renal failure and lesions of the circumflex artery and its branches were excluded, as well as patients with significant comorbidities that were inappropriate for randomization because we selected them for OPCAB procedures. RESULTS Hospital mortality was 2.5%, three patients (3.7%) in group I (on-pump) and one patient (1.2%) in group II (off-pump) (ns). The number of grafts per patients in group I was 1.81 +/- 0.6, and 1.77 +/- 0.68 in group II (p = 0.833). There was no difference in the total operation time 205.10 +/- 54.30 minutes in group I and 189.50 +/- 55.44 in group II (ns). Six patients (7.5%) had myocardial infarction in group I and three (3.7%) in group II (ns). Bleeding in the postoperative period was 680.50 +/- 434.1 mL in the on-pump group and 678.6 +/- 357.0 mL in the off-pump group (ns). Three patients (3.7%) presented transient neurologic dysfunction in group I and six patients (7.5%) in group II (ns). Intensive care stay was 2.4 +/- 1.0 days in the CABG and 2.3 +/- 0.98 days in the OPCAB group (ns). CONCLUSIONS We did not find any statistical difference in hospital mortality and morbidity using on-pump or off-pump techniques for low-risk patients.

Self-expandable aortic stent-grafts for treatment of descending aortic dissections

BACKGROUND Acute aortic dissection is a life-threatening medical condition that is associated with high morbidity and mortality. METHODS Of 198 patients treated with a self-expanding polyester-covered stent-graft for various pathologic aortic conditions in our institution, we selected 70 consecutive patients with type B aortic dissection who were undergoing treatment. The stent-graft was introduced through the femoral artery in the angiography suite, under general anesthesia with systemic heparinization and induced hypotension. RESULTS The procedure was performed in 70 patients; of these, 58 had descending aortic dissection and 12 had atypical dissections. The procedure was successful in 65 patients (92.9%), as documented by exclusion of the false lumen of the thoracic aorta. Eleven patients (18.9%) had persistent blood flow in the false lumen of the abdominal aorta due to distal reentries. Five patients (7.1%) underwent conversion to surgery. Insertion of additional stent-grafts was required in 34 patients (48.6%). At 29 months of follow-up, 91.4% of the patients were alive. CONCLUSIONS Stent-grafts are an important means of treating aortic dissections, which may replace conventional medical treatment of this condition for the majority of patients.

Myocardial revascularization without extracorporeal circulation. Seven-year experience in 593 cases.

The authors present the results of 593 consecutive and non-selected patients who underwent direct myocardial revascularization without extracorporeal circulation in the period September 1981 to December 1988. The results are compared with 3086 patients who underwent conventional bypass surgery over the same period of time. The ages varied from 33 to 80 years (mean = 56) with 40 patients older than 70. The overall mortality in the group without cardiopulmonary bypass (CPB) was 1.7% (10/593) compared with 3.8% for conventional revascularization. Our mortality in the last 3 years has been 0.5% and 0% in the last 203 patients revascularized without CPB. The number of grafts varied from 1 to 5 (average 1.6). The treated arteries were: anterior descending (557), right (282) marginal (5) and circumflex marginal (4). Immediate postoperative complications were fewer and hospital discharge was earlier in the group treated without CPB. The authors conclude that this tactical alternative has the advantages of: lower morbidity and mortality, lower cost and no need for blood transfusion. Drawbacks are the need for greater technical expertise and it seems to be possible in about 19% of all patients who undergo myocardial revascularization.

Surgical Anatomy of the Internal Thoracic Artery

BACKGROUND The internal thoracic artery (ITA) has become increasingly important in coronary artery bypass grafting due to the excellent long-term results. This study reviews its anatomic characteristics. METHODS The ITAs of 100 cadavers were examined and their origin, relation to the phrenic nerve, presence of lateral costal branch; origin of pericardiacophrenic arteries, length, level and type of ITA termination, relation with the transverse muscle of thorax, collateral parietal branches, and distance between the ITA and sternal margins were studied. RESULTS The ITA was present in all cases, originating directly from the subclavian artery or from a common trunk with other arteries. Its length was 20.4 cm on average, and the most frequent level of termination was at the sixth intercostal space, existing as a bifurcation in 93% and as a trifurcation in 7%. The pericardiacophrenic artery originated from the ITA in 89%. The lateral costal branch was present in 15% of the cases. The ITA was covered by the transverse muscle of the thorax for 7.5 cm (average) and was crossed anteriorly by the phrenic nerve in 70.0%. CONCLUSIONS Information provided by this study may contribute to knowledge of its anatomic characteristics and in turn help prevent complications in ITA dissections.

Revolutionary treatment of aneurysms and dissections of descending aorta: the endovascular approach.

BACKGROUND Acute aortic dissection is a life-threatening medical condition. It is associated with high morbidity and mortality. Type B dissections are usually managed clinically during the acute phase. Conventional surgery carries high mortality rates due to the presence of serious complications. We herein present treatment of this condition with a less invasive endovascular approach. Other clinical situations such as penetrating ulcers, intramural hematomas, and true aneurysms of descending aorta were similarly treated. METHODS From December 1996 to March 2002, 191 patients with type B dissections were treated with self-expandable, polyester-covered stents. There were 120 patients (62.8%) with type B dissections, 61 patients (31.9%) with true aneurysms, 6 patients (3.1%) with penetrating ulcers or intramural hematomas, and 4 patients (2.1%) with trauma. Patients with abdominal aneurysms (44) and stents introduced under direct vision through the aortic arch (70) were excluded. The stent graft was delivered in the catheterization laboratory under general anesthesia, with induced hypotension and heparinization. All stents used were made in Brazil (Braile Biomedics, Sao Jose do Rio Preto, SP). RESULTS The procedure was performed in 191 consecutive cases. The success rate was 91.1% (174/191). Success was defined as occlusion of the thoracic intimal tear, or exclusion of the aneurysm without leaks. Hospital mortality was 10.4% (20/191 patients), due to preoperative comorbidities. Six patients required conversion to surgery. No case of paraplegia was observed. An actuarial survival curve showed 87.4% +/- 29% survival in the late follow-up period. CONCLUSIONS Stent grafts are an important development in the treatment of descending aortic aneurysms or dissections. This novel approach may replace conventional surgical treatment of these conditions, with earlier intervention and less morbidity.

Surgical Treatment of Acute Type B Aortic Dissection Using an Endoprosthesis (Elephant Trunk)

BACKGROUND The surgical treatment of acute complicated type B aortic dissection continues to be a challenge and is still associated with high morbidity and mortality rates. METHODS Seventy consecutive patients with an acute type B aortic dissection underwent an elephant trunk procedure through a median sternotomy during deep hypothermic circulatory arrest. An endoprosthesis that was 22 to 24 mm in diameter was inserted through an incision in the arch and held in place with only proximal sutures. RESULTS The mean arrest time was 31.4 +/- 8.7 minutes, and it was possible to adequately position the endoluminal graft in every patient. The procedure was done in association with other procedures in 13 patients. There were six in-hospital deaths not related to the endoprosthesis, and four late deaths. Late reoperation was necessary in 6 patients to manage leakage at the proximal suture line. CONCLUSIONS The insertion of an endoprosthesis through the arch for the management of a complicated acute type B dissection has several advantages over the conventional thoracotomy approach. The hospital mortality rate in this series of 70 patients was 20%, and the actuarial 5-year survival rate was 62.5%. We consider the elephant trunk procedure the treatment of choice in patients with type B acute dissections, regardless of whether the dissection is complicated or not.

Importance of intraoperative transesophageal echocardiography during coronary artery surgery without cardiopulmonary bypass

The goal of this study was to assess left ventricular segmental wall motion (SWM) abnormalities during coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB), and its impact on the immediate postoperative outcome. Transesophageal echocardiography was used intraoperatively in 27 patients (mean age 57 years) who had CABG without CPB. Images obtained with a 5-MHz biplane transesophageal echocardiographic probe in the transgastric and transesophageal planes were recorded before, during, and after 48 coronary artery clampings for saphenous vein or internal mammary artery anastomosis. Transthoracic echocardiography was performed 1 day before surgery and on the seventh postoperative day. During the 48 coronary artery clampings, 31 (64%) new SWM abnormalities were found. At the time of chest closure, complete recovery occurred in 16 (50%) segments, partial recovery in 10 (33%), and no recovery in 5 (17%). On the seventh postoperative day the new SWM abnormalities persisted in all 5 segments without recovery at the end of the surgery and in 2 of 10 (20%)segments with partial recovery (group 1). Group 1 had higher variation on the echocardiographic point score index between the beginning and end of surgery, higher enzymatic levels, more ST-T changes on the electrocardiogram, and more clinical problems than group 2 (patients without new SWM abnormalities on the seventh postoperative day) (P < .05). We concluded that new SWM abnormalities of the left ventricle occur during CABG without CPB as assessed by intraoperative transesophageal echocardiography. Persistence of these abnormalities at the end of surgery may be a predictor of SWM dysfunction and clinical problems in the immediate postoperative period.