Assessment of CABG-related risk in patients with CAD and LVD. Contribution of PET with [18F]FDG to the assessment of myocardial viability.

BACKGROUND: Previous studies have demonstrated that hibernating myocardium can be assessed by [18F]fluorodeoxyglucose ([18F]FDG) and positron emission tomography (PET). This study evaluated the use of [18F]FDG-PET for CABG related risk assessment in patients with coronary artery disease (CAD) and left ventricle dysfunction (LVD). METHODS: We retrospectively evaluated 241 to patients candidate CABG presenting with signs and symptoms of congestive heart failure (CHF) prevailing over ischemic signs. Of the 241 patients, 153 had undergone [18F]FDG-PET as well as conventional assessment: 110 out of 153 (group A) were operated because of PET evidence of hibernation. Of the 241 patients, 88 had not undergone [18F]FDG-PET: 86 out of 88 (group B) were operated on. The outcome of surgical patients was evaluated by considering all major perioperative complications including the use of mechanical and pharmacological support and in-hospital mortality. After hospital discharge, each patient was examined at 1, 4 and every 6 months thereafter. RESULTS: Perioperative use of mechanical supports and inotropic drugs, was significantly lower for the PET selected group (A) than for the non PET selected group (B). Mortality within 30 days of surgery was 0.9% in group A and 19.8% in group B. The only predictors of perioperative outcome were the presence of hibernating tissue and the ejection fraction. CONCLUSIONS: [18F]FDG-PET prior to CABG can be crucial for the assessment of perioperative risk in patients with CAD.

Relation between dobutamine trans-thoracic echocardiography, 99Tcm-MIBI and 18FDG uptake in chronic coronary artery disease.

The relationships between rest conditions of myocardial asynergy, response to dobutamine administration, perfusion and glucose metabolism were examined in 12 patients with chronic coronary artery disease and left ventricular dysfunction. We evaluated (1) rest and stress myocardial perfusion by 99Tcm-methoxyisobutylisonitrile (MIBI) and single photon emission tomography (SPET), (2) rest myocardial segmental wall motion by trans-thoracic echocardiography and low-dose dobutamine, and (3) myocardial metabolism by [18F]-2-fluoro-2-deoxy-D-glucose (18-FDG) and positron emission tomography (PET), in the fasting state. The analysis was carried out on 16 left ventricular myocardial segments. The SPET studies were analysed semi-quantitatively by normalization to the peak activity. Wall motion was assessed by a visual score. An 18FDG index was determined as the tissue/blood pool radioactivity ratio in each segment. The results showed: (1) remarkably good agreement between the number of dobutamine responsive segments and 18FDG positive segments among those that were only moderately hypoperfused and hypokinetic; (2) a smaller number of dobutamine responsive segments than 18FDG positive segments among those that were hypoperfused and akinetic; and (3) the presence of 18FDG in 50% of the segments that were severely hypoperfused and akinetic or dyskinetic and without improvement with dobutamine. These results indicate that in severely hypoperfused and akinetic or dyskinetic segments, trans-thoracic echocardiography under inotropic stimulation provides little additional information compared with that obtained with rest echocardiography and perfusion studies; the assessment of 18FDG uptake provides information that is complementary to that obtained by perfusion assessment, rest and dobutamine trans-thoracic echocardiography.

Myocardial protection with and without leukocyte depletion: a comparative study on the oxidative stress.

We tested the hypothesis that controlled reperfusion with leukocyte-depleted blood could improve myocardial protection by reducing the oxidative stress in patients undergoing myocardial revascularization. Thirty-four patients receiving antegrade/retrograde blood cardioplegia were divided into: group A: 11 patients with ejection fractions (EF) less than 35%, treated with leukocyte-depleted controlled blood reperfusion, group B: 11 patients with EF less than 35% in whom no leukocyte depletion was performed, group C: 6 patients with EF more than 45% treated as group A and group D: 6 patients with EF more than 45% without leukocyte depletion. To asses the oxidative stress, we evaluated total, total oxidized (GSSX), and reduced glutathione (GSH) in coronary sinus plasma, immediately before cross-clamping the aorta (T0), and at 0 (T1), 15 (T2) and 30 (T3) min after unclamping it. In groups A and B a significant shift towards oxidation of redox status of glutathione (GSH/GSSX) at T1 vs T0 was observed. Glutathione redox ratio remained low in group B while in group A it returned to the basal value at T2 with a significant difference from group B at T2 and T3. No differences were observed between groups C and D. In conclusion, our data show that leukocyte-depleted reperfusion can afford a better myocardial protection in patients with left ventricular dysfunction, while it seems unnecessary in patients with normal EF.

Myocardial revascularization with bilateral internal thoracic artery in patients with left main disease or left ventricular dysfunction: an incremental risk?

Although long-term patency of the internal thoracic artery (ITA) is well stated, there is still some concern about its perioperative performance. We considered 122 consecutive patients, 63 with left main disease (LMD; mean age 60 years) and 59 with left ventricular dysfunction (LVD; mean age 59 years) who underwent coronary artery bypass grafting in our Institute from March 1988 to September 1992. Patients with LMD were divided into 2 groups: LMD I: 29 patients receiving only ITA grafts on the left coronary system and LMD II: 34 patients having a single ITA graft on the left coronary system. Patients with LVD were divided into: LVD I: 44 patients operated with bilateral ITA and LVD II: 15 patients receiving a single ITA graft. Perioperative complications in LMD I and LMD II patients were respectively: myocardial necrosis in 2 (6.9%) versus 3 (8.8%), use of intra-aortic balloon pump (IABP) in 2 (6.9%) versus 2 (5.9%); no death occurred in both groups. Perioperative results in groups LVD I and LVD II were: death in 1 patient (2.2%) versus 1 (6.7%), myocardial necrosis in 2 (4.5%) versus 1 (6.7%) and IABP in 4 (9.1%) versus 2 (13.3%). In our experience the use of bilateral ITA grafts in patients with LMD and LVD was not related to an incremental risk. We conclude that LMD and LVD should not be considered as contraindications to the extensive use of arterial conduits.

Myocardial revascularization in patients with severe ischaemic left ventricular dysfunction: a clinical experience.

The benefits of myocardial revascularization in patients with ischaemic left ventricular dysfunction are widely reported. However, myocardial revascularization in such cases is associated with higher mortality and morbidity rates. Sixty patients with severe left ventricular dysfunction underwent myocardial revascularization at the authors' institution. Ejection fraction was assessed by angiocardioscintigraphy before and at 3 months after surgery. All patients underwent elective surgery and received complete myocardial revascularization. Myocardial protection was achieved using Buckberg's protocol. One perioperative death occurred. Weaning from cardiopulmonary bypass required inotropic drug therapy in 22 cases and aortic counterpulsation in nine. Perioperative myocardial infarction occurred in three patients with no further haemodynamic impairment. The mean postoperative ejection fraction was 41.0%, compared with a mean preoperative value of 26.5%. The extent of left ventricular functional improvement was greatest in those patients having the worst preoperative left ventricular function. It is concluded that, with this technique, myocardial revascularization can be achieved in patients with severe left ventricular dysfunction with an acceptable operative mortality.

Identification and revascularization of hibernating myocardium in angina-free patients with left ventricular dysfunction.

We examined 17 angina-free patients with left ventricular dysfunction, referred for surgical decision-making, who presented with no or few signs and symptoms of myocardial ischemia according to treadmill stress test. On cardiac catheterization they were affected by severe multi-vessel coronary artery disease; the mean left end-diastolic pressure of this population was 26.3 +/- 5.5 mm Hg (mean +/- SD) and their mean ejection fraction was 27.6 +/- 4.9% (mean +/- SD). They all were investigated for the presence of viable myocardium by the combined assessment of cardiac perfusion and metabolism using single photon emission tomography with [99mTc] labelled hexakis-2-methoxy-isobutyl-isonitrile [99mTc]MIBI/SPET) and positron emission tomography with [18F]-2-fluoro-2-deoxy-D-glucose ([18F]FDG/PET), respectively. Patients were considered for coronary surgery when [18F]FDG was detectable in at least two cardiac segments with wall motion abnormalities and perfusion defects. Nine patients were operated on, six were medically treated and two were scheduled for heart transplantation. We recorded no in-hospital mortality. At a mean follow-up of 28.4 +/- 9.8 (mean +/- SD) months all surgical patients were alive and their NYHA functional classes have improved, except in one case. Among the patients refused for bypass surgery, three are in stable conditions, three have worsened clinical statuses and two died while waiting for heart transplantation. In conclusion, for patients with bypassable coronaries, left ventricular dysfunction and lack of angina, successful coronary revascularization may be predicted by the presence of viable myocardium demonstrated with positron emission tomography.

Myocardial revascularization with bilateral internal thoracic artery in patients with left main disease: an incremental risk?

Although the long-term patency of the internal thoracic artery (ITA) has been well proved, there is still some concern about its preoperative performance. We considered 80 patients with left main disease (mean age 60.2 years) who underwent coronary artery bypass grafting in our institute from March 1988 to September 1992. Patients with left main disease were divided into 2 groups: group I-38 patients receiving only ITA grafts on the left coronary system and group II-42 patients having a single ITA graft together with saphenous vein grafts on the left coronary system. No patients in group I received a saphenous graft on the left coronary system and three patients with right coronary artery involvement received total arterial myocardial revascularization with the use of the inferior epigastric artery. Perioperative complications in group I and group II patients were, respectively: myocardial necrosis in 2 (6.9%) and 3 (8.8%), use of intraaortic balloon pump in 2 (6.9%) and 2 (5.9%). No death occurred in either group. In our experience, the use of bilateral ITA grafts in patients with left main stenosis was not related to an incremental risk. We conclude that left main disease should not be considered as counterindication to the extensive use of arterial conduits.

[Myocardial revascularization in patients with compromised left ventricular function]. / Rivascolarizzazione miocardica in pazienti con funzione ventricolare sinistra compromessa.

From March 1988 to March 1992, 69 patients with coronary artery disease (CAD) and left ventricular dysfunction (LVD) were referred to our Institute for surgical decision making. Sixty-nine (8.2%) had LVD. In 39/69 patients we performed the identification of viable myocardium with the use of [18F] FDG/PET in fasting conditions. We divided patients with LVD into 3 groups: Group A (30 patients) operated on without preoperative [18F] FDG/PET, Group B (32 patients) with FDG uptake in akinetic segments, and Group C (7 patients) with no FDG uptake; there was no significant difference among the 3 groups in age, sex, CAD, risk factors and ejection fraction EF (Group A: 29.1 +/- 6.6%, range 16-40; Group B: 32.9 +/- 6.5%, range 20-40; Group C: 26.5 +/- 6.8%, range 18-37). All patients underwent [99mTc] MIBI/SPET to assess perfusion at rest and [99mTc] MIBI first pass radionuclide angiography to assess the EF. The study of perfusion and EF was repeated 6 months postoperatively in Group A and B. Myocardial protection was achieved according to the Buckberg protocol. Operative results in Group A and B were respectively: in-hospital deaths 2 (6.6%) versus 0 (NS), perioperative myocardial infarction 1 (3.3%) versus 1 (3.1%) (NS), IABP 10 (33.3%) versus 4 (12.5%) (p = 0.048). Postoperative EF improved both in Group A (35.1 +/- 7.1%, range 20-50; p = 0.01) and in Group B (44.2 +/- 7.7%, range 26-62; p < 0.001). In Group C 6/7 patients were scheduled for heart transplantation according to standard criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Total arterial myocardial revascularization.

The superiority of the internal thoracic artery (ITA) compared with venous conduits in terms of late graft patency is nowadays well documented. The inferior epigastric artery (IEA) was recently proposed as an alternative conduit for coronary artery surgery with good early clinical and angiographic results. To improve the benefits from myocardial revascularization, we expanded the use of these arterial conduits. From June 1988 to December 1991, 615 patients underwent coronary surgery in our institute. In 138 of them (22.4%) we performed total arterial myocardial revascularization placing 2 or more coronary anastomoses. An average of 2.37 anastomoses per patient were placed with the maximum number of 6 in one case. Only one patient died of cardiac related causes (0.72%). Perioperative morbidity included myocardial infarction and sternal dehiscence in 5 patients each (3.6%). No stroke or reoperation for bleeding occurred. No rectus muscle necrosis was recorded. Accurate preoperative planning of graft placement allows for the performance of as many as 6 distal anastomoses using bilateral ITA and single IEA grafts only, thus completely revascularizing most of the hearts with three-vessel disease. In our series this procedure was not reflected in an increase in the perioperative morbidity. We choose an elective total arterial revascularization in younger (under 65 years) patients who, while showing a lower incidence of complications in our study, are likely to derive the highest benefits from the good durability of ITA and hopefully IEA grafts.

Presurgical identification of hibernating myocardium by combined use of technetium-99m hexakis 2-methoxyisobutylisonitrile single photon emission tomography and fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography in patients with coronary artery disease.

We tested the possibility of identifying areas of hibernating myocardium by the combined assessment of perfusion and metabolism using single photon emission tomography (SPET) with technetium-99m hexakis 2-methoxyisobutylisonitrile (99mTc-MIBI) and positron emission tomography (PET) with fluorine-18 fluoro-2-deoxy-D-glucose (18F-FDG). Segmental wall motion, perfusion and 18F-FDG uptake were scored in 5 segments in 14 patients with coronary artery disease (CAD), for a total number of 70 segments. Each subject underwent the following studies prior to and following coronary artery bypass grafting (CABG): first-pass radionuclide angiography, electrocardiography gated planar perfusion scintigraphy and SPET perfusion scintigraphy with 99mTc-MIBI and, after 16 h fasting, 18F-FDG/PET metabolic scintigraphy. Wall motion impairment was either decreased or completely reversed by CABG in 95% of the asynergic segments which exhibited 18F-FDG uptake, whereas it was unmodified in 80% of the asynergic segments with no 18F-FDG uptake. A stepwise multiple logistic analysis was carried out on the asynergic segments to estimate the postoperative probability of wall motion improvement on the basis of the preoperative regional perfusion and metabolic scores. The segments with the highest probability (96%) of functional recovery from preoperative asynergy after revascularization were those with a marked 18F-FDG uptake prior to CABG. High probabilities of functional recovery were also estimated for the segments presenting with moderate and low 18F-FDG uptake (92% and 79%, respectively). A low probability of functional recovery (13%) was estimated in the segments with no 18F-FDG uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic valve replacement in Cogan's syndrome.

Cogan's syndrome is a systemic vasculitis of autoimmunologic origin. The main disturbances involve the eye, the ear and the heart, but many other structures can also be affected. Nonspecific abnormal laboratory findings are also present. The disease usually involves a cranial nerve, followed by aortitis which can affect the aortic valve and, more rarely, the cusps of the valve. Aortic lesions strongly influence the course of the disease and therefore the prognosis. When choosing the type of valve replacement, long-term corticosteroid therapy and the age and sex of the patient must be taken into account.