Quantitative analysis of myocardial blood flow in surgically revascularized and not revascularized myocardial segments. A pilot PET study.

PURPOSE: To prospectively compare changes in myocardial blood flow (MBF) and myocardial flow reserve (MFR) in multivessel coronary artery disease (MVCAD) patients undergoing incomplete revascularization (IR) versus complete revascularization (CR) by coronary artery bypass grafting (CABG). METHODS: Seven male patients (age 68 ± 9 years) with MVCAD underwent myocardial perfusion PET/CT with [13N]ammonia before and at least 4 months after CABG. Segmental resting and stress MBF as well as MFR were measured. Resting and during stress left ventricle ejection fraction (LVEF) were also calculated. RESULTS: Three patients (43%) underwent CR and four (57%) IR. Among 119 myocardial segments, 101 (85%) were revascularized, and 18 (15%) were not. After CABG, stress MBF (mL/min/gr) and MFR are significantly increased in all myocardial segments, with a greater increase in the revascularized segments (p = 0.013). In both groups, LVEF significantly decreased during stress at baseline PET (p = 0.04), but not after CABG. CONCLUSION: Stress MBF and MFR significantly improve after CABG in both revascularized and not directly revascularized myocardial segments. IR strategy may be considered in patients with high surgical risk for CR.

Cerebrospinal-fluid drain-related complications in patients undergoing open and endovascular repairs of thoracic and thoraco-abdominal aortic pathologies: a systematic review and meta-analysis.

BACKGROUND: Cerebrospinal-fluid (CSF) drainage is recommended by current guidelines for spinal protection during open and endovascular repairs of thoracic and thoraco-abdominal aortic aneurysms. In the published literature, great variability exists in the rate of CSF-related complications and morbidity. Herein, we perform a systematic review and meta-analysis on the incidence of CSF drainage-related complications, and compare the complication rates between open and endovascular repairs. METHODS: The systematic review was conducted according to the Meta-Analysis of Observational Studies in Epidemiology guidelines. Thirty-four studies (4714 patients) were included in the quantitative analysis. The CSF drainage-related complications were categorised as mild, moderate, and severe. Pooled event rates for each complication category were estimated using a random-effect model. Random-effect uni- and multivariable meta-regression analyses were used to assess the effect of aortic-repair approach (open vs endovascular) and the CSF drainage criteria on CSF drainage-related complications. RESULTS: The pooled event rates were 6.5% [95% confidence interval (CI): 4.3-9.8%] for overall complications, 2% (95% CI: 1.1-3.4%) for minor complications, 3.7% (95% CI: 2.5-5.6%) for moderate complications, and 2.5% (95% CI: 1.6-3.8%) for severe complications. The drainage-related-mortality pooled event rate was 0.9% (95% CI: 0.6-1.4%). The uni- and multivariable meta-regression analyses showed no difference in complication rates between the open and endovascular approaches, or between the different CSF drainage protocols. CONCLUSION: The complication rate for CSF drainage is not negligible. Our results help define a more accurate risk-benefit ratio for CSF drain placement at the time of repair of thoracic and thoraco-abdominal aneurysms.

Contemporary results for isolated aortic valve surgery.

BACKGROUND: We aimed to give an overview of the contemporary status of aortic valve replacement. MATERIALS AND METHODS: This single-center prospective study was initiated in January 2003. From this date on, every patient with aortic valve disease admitted to our hospital was reviewed by a cardiologist and a surgeon to determine eligibility for replacement. In no instance was the operation denied in the absence of surgical consultation. All operations were performed using a median sternotomy, with cardiopulmonary bypass and cardioplegic arrest. RESULTS: A total of 873 cases were screened until the end of the study. We identified three groups of patients: Group 1 (inoperable cases) consisted of 15 patients (1 %); Group 2 (high-risk cases) included 99 patients with an additive EuroSCORE ≥ 10 or an expected mortality > 20 % (logistic model); Group 3 (moderate- to low-risk cases) consisted of 759 patients with an additive EuroSCORE < 10 or an expected mortality < 20 %. In-hospital mortality was 6.0 % (6/99) for Group 2 and 0.3 % (3/759) for Group 3. Major complications occurred in 5 patients of Group 2 (5 %) and in 9 patients of Group 3 (1.1 %). At predischarge echocardiography, 99.3 % of the implanted valves were perfect. At a follow-up of 28.9 ± 12.3 months 798/849 patients were alive; 89 % of them (711) were in NYHA 1-2. CONCLUSIONS: Surgical aortic valve replacement provides excellent results and has a low operative mortality even in high-risk patients. Surgical consultation for every aortic patient resulted in an extremely low rate of surgery refusals. Our data should be regarded as a benchmark for transcatheter techniques.

Impaired coronary and myocardial flow in severe aortic stenosis is associated with increased apoptosis: a transthoracic Doppler and myocardial contrast echocardiography study.

OBJECTIVE: To test the hypothesis that impaired coronary and myocardial blood flow are linked with increased myocyte apoptosis, thus establishing a link between pressure overload and left ventricular (LV) remodelling. METHODS AND RESULTS: Peak diastolic coronary blood flow velocity (CBFV) was evaluated at transthoracic Doppler echocardiography, and signal intensity (SI) and the rate of SI rise (beta) were measured at myocardial contrast echocardiography in 11 patients with severe aortic stenosis and LV hypertrophy. In the same patients, biopsies were obtained from the anterolateral LV free wall during surgery and analysed for cardiomyocyte apoptosis. LV mass corrected CBFV (CBFVI) was significantly lower in patients than in controls (median 0.100 cm.g/s (interquartile range 0.07-0.115) v 0.130 cm.g/s (0.130-0.160), p = 0.002). Similarly, SI*beta was significantly lower in patients than in controls (11 1/s (8-66) v 83 1/s (73-95), p = 0.001). Apoptotic rate was increased in aortic stenosis more than 100-fold versus controls (1.2% (0.8-1.4) v 0.01% (0.01-0.01), p < 0.001) and inversely correlated with lower CBFVI and SI*beta (r = -0.77, p = 0.001 for both). CONCLUSIONS: Patients with severe aortic stenosis and LV hypertrophy have impaired myocardial perfusion, which is associated with enhanced cardiomyocyte apoptosis. Impaired myocardial perfusion and the ensuing oxygen demand-supply imbalance may, at least partially, be responsible for increased apoptosis and possible transition to heart failure, thus establishing a link between pressure overload, LV remodelling, and heart failure.

Clinical and angiographic effects of chronic calcium channel blocker therapy continued beyond first postoperative year in patients with radial artery grafts: results of a prospective randomized investigation.

BACKGROUND: This study was conceived to elucidate the clinical and angiographic effects of chronic calcium channel blocker therapy (CCCBT) continued after the first postoperative year in patients in whom the radial artery (RA) was used for myocardial revascularization. METHODS AND RESULTS: Patients who received RA grafts at our institution and who at 1 year had no scintigraphic evidence of ischemia in the RA territory or angiographic evidence of RA malfunction (n=120) were randomly assigned to continue (n=63) or suspend (n=57) the CCCBT with diltiazem (120 mg/d). After 5 years, all patients were reassessed clinically and by stress myocardial scintigraphy, and 87 of them (45 from the continued group that continued CCCBT and 42 from the group that suspended CCCBT) were restudied angiographically. No differences regarding either the clinical and scintigraphic results or the RA angiographic status were demonstrated between the 2 groups. CONCLUSIONS: After the first postoperative year, the continuation of CCCBT does not affect RA graft patency or clinical and scintigraphic results.

An unusual source of massive intra-abdominal hemorrhage during cardio-pulmonary bypass.

Intra-abdominal hemorrhage occurring while on cardio-pulmonary bypass (CPB) is a rare and potentially lethal event during coronary artery bypass procedures. We herein report an unusual case in which massive intra-abdominal bleeding during CPB originated from a previously undiagnosed ovarian tumor, leading to acute anemization and hemodynamic instability and requiring emergency gynecologic surgery.

Should severe monolateral asymptomatic carotid artery stenosis be treated at the time of coronary artery bypass operation?

OBJECTIVE: The optimal treatment of severe monolateral asymptomatic carotid artery stenosis (SMACS) in patients undergoing coronary artery bypass grafting (CABG) is still controversial. MATERIALS AND METHODS: This study is based on the in-hospital and mid-term (>5 years) clinical results of a cohort of 139 consecutive CABG patients with SMACS operated at our Institution between January 1989 and December 1995. In the first 73 patients (no carotid surgery group), the SMACS was left untouched at the time of coronary surgery, whereas in the remaining 66 (carotid endoarterectomy group), the carotid stenosis was treated either immediately before or concomitantly with the CABG procedure (depending on the severity of the anginal symptoms). RESULTS: The overall preoperative characteristics of the patients were comparable. The in-hospital results were similar between the two groups with regard to mortality, stroke and major postoperative complications. However, at mid-term follow-up, significantly more patients of the no carotid surgery group suffered cerebral events (transient or permanent) ipsilateral to the SMACS or the lesion had to be operated on. CONCLUSIONS: The concomitant treatment (either staged or simultaneous) of SMACS at the time of CABG does not influence the in-hospital results, but confers significant neurological protection during the years after the operation.

The unclampable ascending aorta in coronary artery bypass patients: A surgical challenge of increasing frequency.

BACKGROUND: The unclampable ascending aorta (UAA) is a condition increasingly encountered during CABG procedures. We report our experience with CABG patients with UAA and place particular emphasis on the preoperative diagnosis and surgical management. METHODS AND RESULTS: UAA was diagnosed in 211 of 4812 consecutive CABG patients (4.3%). On the basis of the chest radiograph, echocardiogram, and coronary angiograph, a preoperative diagnosis was achieved in only 58 patients (27.4%). An age of >70 years, diabetes, smoking, unstable angina, diffuse coronaropathy, and peripheral vasculopathy were all predictors of UAA. Patients were treated with hypothermic ventricular fibrillation (no-touch technique n=129) or beating heart revascularization (no-pump technique n=82) depending on the possibility of founding an arterial cannulation site. The overall in-hospital mortality rate was 2.8% (6 of 211) with no differences between the 2 surgical strategies. The no-touch technique was associated with a greater incidence of neurological complications (stroke and transient ischemic attack), renal insufficiency, and stay in the intensive care unit and hospital. However, at midterm follow-up, more patients of the no-pump group had ischemia recurrence. CONCLUSIONS: A preoperative diagnosis of UAA is achievable only in a minority of patients, which highlights the necessity revising the current diagnostic protocols. The use of the no-touch technique is associated with an high perioperative risk but a superior possibility of complete revascularization, whereas adoption of the no-pump strategy ensures a smoother postoperative course at the expense of an higher incidence of ischemia recurrence.

Midterm endothelial function and remodeling of radial artery grafts anastomosed to the aorta.

BACKGROUND: The purpose of this study was to elucidate the midterm endothelium-dependent vasodilatory capacity of radial artery grafts anastomosed to the aorta, as well as their morphometric evolution with the time. METHODS: Five years after surgery we evaluated the response of aorta-anastomosed radial artery grafts to the endovascular infusion of acetylcholine in 11 of the first 61 patients operated on at our institution, and we compared it to the response with that of internal thoracic artery grafts. Moreover, the first 20 patients who had a perfect radial artery graft on angiography at 1 year were restudied at 5 years and subjected to a comparative analysis of the diameters of the radial artery graft and the grafted coronary arteries. RESULTS: At midterm angiography, dilation of the 2 types of grafts was similar in response to acetylcholine administration (radial artery, from 2.61 +/- 0.39 to 2. 90 +/- 0.34 mm; internal thoracic artery, from 2.68 +/- 0.21 to 2.93 +/- 0.27 mm; P =.01 for both). The diameters of aorta-anastomosed radial artery grafts and grafted coronary arteries increased between both 1 and 5 years according to angiographic studies (radial artery grafts, from 2.08 +/- 0.45 to 2.54 +/- 0.53 mm; grafted coronary arteries, from 1.92 +/- 0.47 to 2.18 +/- 0.41 mm; P <.001 for both), but the increase was greater for the radial artery grafts (P <.001). CONCLUSIONS: Aorta-anastomosed radial artery grafts maintain an appreciable capacity for endothelium-dependent vasodilatation 5 years after implantation and undergo a progressive increase in luminal diameter with time. These observations contradict the presumed tendency for progressive fibrous intimal hyperplasia to develop in radial artery grafts.

Are pulmonary homografts which were subjected to pulmonary hypertension more appropriate for aortic valve replacement than normal pulmonary homografts? A long-term multicentric echography study.

OBJECTIVE: To compare long-term results of the European Homograft Bank (LHB) cryopreserved pulmonary homograft in left ventricular outflow tract (LVOT) subjected to pulmonary hypertension with those subjected to normal pulmonary pressure. The mid-term study of this material published in 1997 showed different results. METHODS: Statistical analysis is calculated by the Kaplan-Meier survival curves, while differences in prevalence by the Log-Rank test. RESULTS: Follow-up (FU) was available in 69 cases (76.7%): 46 in group 1 and 23 in group 2. Five patients have been excluded from the study because of early homograft explantation (technical problems or early valve incompetence). Fourteen out of 43 cases of group 1 (32. 6%) and seven out of 21 cases of group 2 (33.3%) have been explanted after 2.5-88 months and 7-88 months, respectively. Significant echography changes have been found in 19 of 43 (44.18%) of group 1 and 11 of 21 cases (52.38%) of group 2 during the follow-up. Histology showed essentially wear and tear induced lesions. Mean FU was 36.9 (range, 6-88) and 41.3 months (range, 4-88) for group 1 and 2, respectively. No significant difference in the long-term outcome have been found between the two groups (P=0.38). CONCLUSION: Contrary to our previous echocardiography study of mid-term implants the long-term follow up of the PHGs implanted in the LVOT did not show better function of the pulmonary homografts subjected to pulmonary hypertension than those with normal pulmonary pressure. The high failure rate of the PHGs should discourage their use for LVOT reconstruction. Further echocardiography studies of remaining PHGs implanted in the LVOT, and gross and microscopic explant studies are required to judge on the definitive outcome of these grafts.

Hemodynamic and functional consequences of radial artery removal for coronary artery bypass grafting.

Five years after surgery the echo-Doppler characteristics of the forearm circulation and the transcutaneous oxygen and carbon dioxide pressures of the operated and control arm were determined at rest and under conditions of hand exercise in 34 patients who received a radial artery graft for myocardial revascularization. Doppler measurements showed the ulnar compensation to radial artery removal, and transcutaneous measurements demonstrated a moderate degree of exercise-induced hand ischemia on the operated site.

Effect of skeletonization of the internal thoracic artery on vessel wall integrity.

BACKGROUND: This study was conceived to evaluate the effect of internal thoracic artery (ITA) skeletonization on vessel wall integrity. METHODS: Forty consecutive patients undergoing coronary artery bypass were randomized to receive a skeletonized (n = 22) or a pedicled (n = 18) ITA graft. ITA harvesting was performed by 2 experienced surgeons using the same instrumentation and technique. Specimens were examined by light and electron microscope in order to assess vascular wall integrity. A specific immunohistochemical staining and a computerized method were used to quantify the degree of endothelial integrity after surgical preparation. RESULTS: Morphologic analysis revealed 2 cases of limited subadventitial hemorrhage (one for each group) and no case of major arterial damage. Immunohistochemical staining demonstrated an extremely high degree of maintenance of the endothelial integrity in both groups (97.2% +/- 1.9% in the skeletonized and 96.8% +/- 2.1% in the pedicled one; p = 0.53). CONCLUSIONS: Skeletonization does not affect ITA wall integrity in humans submitted to coronary artery bypass procedures.

Internal mammary artery grafts and competitive flow. Controversies persist.

We report one case in which chronic native competitive flow from an almost normal target coronary artery did not influence IMA graft patency. This patient underwent control postoperative angiography 11 months after surgery and the mammary artery-left anterior descending graft was found to be normofunctioning despite the fact that the coronary artery showed no residual stenosis.

Superior extension of intraoperative brain damage in case of normothermic systemic perfusion during coronary artery bypass operations.

OBJECTIVE: Despite the controversies on the potential detrimental effects of normothermic cardiopulmonary bypass on neurologic outcome, to date no correlation between the severity of intraoperative brain lesions and the cardiopulmonary bypass temperature used at operation has been reported. This study compares the prevalence and the severity of brain lesions in patients who underwent operation in condition of normothermic versus hypothermic systemic perfusion. METHODS: Data are derived from the analysis of 2987 consecutive primary isolated myocardial revascularizations performed at our institution between April 1990 and January 1997. Of these cases, 1385 procedures were hypothermic and 1602 procedures were normothermic systemic perfusion. In all cases the neurologic outcome and extent of ischemic areas were prospectively recorded. RESULTS: Overall, 31 patients had a perioperative stroke (1.0%). The prevalence of neurologic events was similar in the 2 groups (15 cases in the hypothermic group and 16 cases in the normothermic perfusion group; P, not significant). However, the mean Glasgow Outcome Scale score and computed tomography-demonstrated extent of brain lesions were significantly worse in the normothermic group. CONCLUSIONS: Although the prevalence of intraoperative stroke was similar with hypothermic or normothermic cardiopulmonary bypass, the use of normothermic systemic perfusion was associated with more extended brain damage at computed tomographic scan and with a worse neurologic outcome. These results demand caution in the use of normothermic cardiopulmonary bypass and claim further investigation on the neurologic safety of normothermia.

Repair of an ascending aorta pseudoaneurysm by way of superior ministernotomy.

A wide ascending aorta pseudoaneurysm occurring 10 years after uncomplicated aortic valve replacement was successfully repaired using a superior ministernotomy and femoral-femoral cannulation. In this setting, a limited sternal incision minimized the risk of pseudoaneurysm rupture during dissection and allowed safe isolation of the target cardiac structures.