Effectiveness Of Surgical Revascularization Research Articles

The first application of intraoperative mri for analysis of cerebral perfusion in surgical brain revascularization

Effectiveness of surgical revascularization in patients with chronic cerebral ischemia depends on restoration of circulation in the damaged artery. Modern methods do not take into account dynamic changes in cerebral perfusion after extra-intracranial microvascular anastomosis (EICMA) and do not allow timely localizing the areas of persistent perfusion deficit. We propose a new method for determining the tactics of surgical cerebral revascularization based on intraoperative MRI (iMRI) perfusion data. This method provides the earliest information on intraoperative brain reperfusion. To develop the principles of dynamic assessment of cerebral blood flow using intraoperative ASL perfusion during surgical revascularization in patients with chronic cerebral ischemia and to determine the indications for additional anastomoses. Surgical revascularization with intraoperative MRI perfusion was performed in 27 patients between March 2022 and April 2023. There were 10 patients with post-thrombotic occlusion of internal carotid artery, 4 patients with occlusion of middle cerebral artery and 13 patients with moyamoya disease. All patients underwent MRI before surgery. After imposing the first EICMA, all patients underwent ASL perfusion for analysis of residual hypoperfusion zones, signs of local hyperperfusion and indications or contraindications for additional revascularization with the second donor branch. In all cases, iMRI made it possible to determine the tactics of brain revascularization using one or two EICMA. In 17 cases, ASL perfusion confirmed the targeted improvement of cerebral blood flow (CBF) in the entire hemisphere or middle cerebral artery basin. Only one EICMA was imposed in these cases. In 10 cases, a single anastomosis was insufficient for restoration of blood flow. These patients underwent additional revascularization with the second donor branch (35.7%). In all cases, we achieved significant quantitative improvement in CBF and volume of brain tissue with restored blood flow (ASPECTS scale). A single EICMA was followed by increase in CBF and areas of restored blood flow by almost 2 times (22.7±9.6 ml/100 g/min and 4.7±1.8 scores (ASPECTS) before surgery vs. 39.4±16.4 ml/100 g/min and 4.7±1.8 scores after EICMA). In the double EICMA group, these parameters increased by almost 3 times (18±3.1 ml/100 g/min and 3.8±0.9 scores before surgery vs. 57±11.4 ml/100 g/min and 7.7±1.5 scores after double EICMA). All patients had no complications. Neurological status improved immediately after surgery in 9 patients (33.3%), stable postoperative period was observed in 12 cases (44.4%). Six (22.2%) patients had transient neurological deficit associated with hyperperfusion syndrome that regressed within a few days after surgery. There were no persistent ischemic complications. Intraoperative ASL perfusion is an effective and informative tool for determining the degree of restoration of blood flow. We can timely adjust surgical strategy, determine the indications or contraindications for additional revascularization and exclude early ischemic complications using this method.

The effect of surgical revascularization on the mechanical properties of cryopreserved bone allograft in a porcine tibia model.

Cryopreserved bone allografts(CBA) are susceptible to infection, nonunion, and late stress fracture. Althoughsurgical revascularization by intramedullary implantation of an arteriovenous bundle (AV bundle) generates a neoangiogenic blood supply, there is potential for vascular ingrowth-mediated bone resorption to weaken the graft. For this reason, we have evaluated changes in CBA mechanical properties of structural tibial allografts with and without surgically induced angiogenesis. Cryopreserved tibia bone allografts were transplanted to reconstruct a 3.5 cm segmental tibial defect in 16 Yucatan mini pigs. Surgical revascularization was performed in half by implantation of a cranial tibial AVbundle, (revascularization group). A control group of identical size had a ligated AV bundle implanted, (ligated group). At 20 weeks micro-computed tomography (CT) measured bone mineral density (BMD) as well as bone union. Reference point indentation (RPI) compared cortex material properties, and axial compression determined the allotransplant compressive modulus. Seven of eighttibiae in the angiogenesis group were healed at both junction points at 20 weeks. Only fourof eighttibiae healed in the ligated control group. There was no significant difference between the revascularization and ligated control groups in BMDand axial compression test. Similarly, RPI parameters were statistically equal. In paired comparisons with contralateral tibias, however, some RPI values were significantly worse in the ligated control group tibiae. This study demonstrates no adverse effect of surgical angiogenesis on cryopreserved structural bone allograft biomechanical properties in a large animal orthotopic segmental tibial defect model. These data suggest the potential value of surgical angiogenesis in clinical limb-sparing reconstructive surgery.

VENOUS CONDUITS IN CORONARY SURGERY: OLD PROBLEMS — NEW SOLUTIONS

The introduction of autovenous coronary artery bypass grafting (CABG) marked the era of surgical revascularization in patients with coronary artery disease. It provided effective treatment for angina and significantly improved the long-term prognosis. Venous transplants today remain the most popular conduits in coronary surgery due to their availability, ease of harvesting, and the absence of length restrictions. Despite the advantages of autovenous CABG, the main disadvantage is the high incidence of venous graft failure, which represents an important and unresolved problem in cardiac and cardiovascular surgery. On the other hand, the traditional allocation of a large saphenous vein implies the dissection of soft tissues throughout the length of the isolated conduit. Traumatic dissection causes a long-lasting persistent pain syndrome after surgery, frequent abnormalities in skin sensitivity, and a high incidence of wound complications in the lower extremities. These complications lengthen the period of rehabilitation of patients and worsen the quality of life. There is an approach of isolating the vein in a block with surrounding tissues to optimize the long-term functioning of the venous shunt, however, this technique is even more traumatic than the traditional method, and therefore its use is limited in practice. On the other hand, the introduction of minimally invasive methods of isolation allowed to reduce the incidence of wound complications and to improve the cosmetic result, but there is no convincing data regarding the effect on the consistency of shunts in the long-term postoperative period. The problems associated with the use of venous conduits in CABG are multifaceted, and their solutions are necessary to improve the effectiveness of surgical revascularization.

Mid-term results of coronary bypass graft surgery in patients with ischaemic left ventricular systolic dysfunction and no detected myocardial viability

There are concerns about effects of surgical revascularization on patients with ischaemic systolic dysfunction when no signs of myocardial viability have been detected by nuclear imaging preoperatively. We reviewed our data to determine the efficacy of coronary bypass graft in this special patient cohort. A retrospective review with prospectively collected clinical data was conducted on 87 consecutive patients between 2000 and 2012 whose left ventricular ejection fraction was less than 40%. All patients received positron emission tomography examination before undergoing coronary artery bypass graft and showed no signs of myocardial viability. Improvements in ejection fraction, postoperative re-examination of myocardial viability by nuclear imaging and freedom from major cardiac events were observed. Survival was calculated using Kaplan-Meier analysis. The 30-day mortality rate was 7%. Ejection fraction improvement (defined as over 5%) was observed in 13 (16%) patients within 6 months postoperatively. Ejection fraction improvement was observed in 46 (58%) patients by the end of the first year and 50 (63%) patients by the second year. It was noted that 25 (32%) and 43 (54%) patients progressed to heart functional class I or II at 1 and 5 years, respectively. Positron emission tomography examination showed enhanced myocardial viability in the non-viable ventricular wall segment in 53 (67%) patients at 1 year. Freedom from major adverse cardiac events was observed in 56 (71%) patients at 1 year and 47 (60%) patients at 5 years. Survival rates were 82 and 66% at 1 and 5 years, respectively. Coronary artery bypass graft proved to be a positive choice of treatment for patients with severe ischaemic systolic dysfunction when there was no viable myocardium detected through nuclear imaging.

Abstract WP61: A Novel Application of Four-dimensional Magnetic Resonance Angiography Using Arterial Spin Labeling for Assessment of Postoperative Cerebral Hemodynamic Changes in Moyamoya Disease

Introduction: Recently, four-dimensional magnetic resonance angiography without contrast enhancement using arterial spin labeling (ASL-4D MRA) has become available to visualize the intracranial arteries. However, few reports are available about the efficacy of ASL-4D MRA in moyamoya disease (MMD). Hypothesis: We hypothesized that postoperative hemodynamic changes in MMD patients could be evaluated using ASL-4D MRA. Methods: This study included 26 hemispheres of 21 patients who underwent combined direct and indirect revascularization for MMD. ASL-4D MRA was serially performed before and after surgery. We assessed the time phases where signals of the arteries were detected on ASL-4D MRA in order to analyze perioperative changes in cerebral hemodynamics. Results: The signals of the anastomosed arteries on ASL-4D MRA were detected and disappeared at significantly earlier time phase after surgery than before. This change in acute period was moderated in chronic period after surgery. Postoperative hyperperfusion was observed in 12 of 26 hemispheres within 7 days after surgery. The signals of the arteries were detected significantly earlier in hemispheres with hyperperfusion than those without. In cases with hyperperfusion, ASL-4D MRA demonstrated high intensity of peripheral middle cerebral artery (MCA) around anastomosed region in early time phase (Figure). This “early hyperintensity of MCA” was observed in all cases with hyperperfusion and corresponded to the timing of the occurrence of hyperperfusion. Furthermore, this hyperperfusion-specific sign could not be detected by routine TOF MRA. Conclusions: Noninvasive ASL-4D MRA successfully evaluated perioperative dynamic changes of cerebral blood flow and the effect of surgical revascularization in MMD. This next generation modality could also visualize cerebral hemodynamics in cases with postoperative hyperperfusion and would be quite useful for appropriate postoperative management.

The effect of surgical revascularization on different timing after ST-elevation myocardial infarction on patients with ischemic heart disease and left ventricular dysfunction

To analysis the influence of surgical revascularization on different timing after ST-elevation myocardial infarction (STEMI) on patients with coronary artery disease and left ventricular dysfunction. Clinical data of 225 patients admitted from January 2003 to July 2012 with history of STEMI and left ventricular dysfunction (ejection faraction<50%) who underwent isolated coronary artery bypass grafting was retrospectively reviewed. There were 186 male and 39 female patients. According to the timing of surgical revascularization after STEMI, the patients were divided into early revascularization group (ER group, <21 days), mid-term revascularization group (MR group, 21 to 90 days) and late revascularization group (LR group, >90 days). There were 20 male and 9 female patients in ER group with mean age of (63 ± 10) years, 48 male and 16 female in MR group with mean age of (63 ± 8) years, 118 male and 14 female in LR group with mean age of (62 ± 10) years, respectively. Thirty-day post-operative mortality and major complications were determined as the endpoints to evaluate the early results of operation. The 30-day post-operative mortality were 3.4%,0 and 2.3% among three groups respectively and there was no statistic difference between groups (χ(2) = 2.137, P = 0.330).Low cardiac output syndrome mortality were 13.8%, 3.1% and 2.3% among three groups respectively and there was statistic difference between groups (χ(2) = 8.344, P = 0.015). The ejection fractions was significantly improved in all the three groups from 42% ± 6%, 41% ± 6% and 42% ± 6% preoperatively to 46% ± 7%, 45% ± 10% and 45% ± 9% postoperatively (t = -3.378 to -2.339, all P < 0.05). The left ventricular end diastolic dimension were significantly reduced in MR group and LR group from (54 ± 6) mm and (55 ± 6) mm preoperatively to (47 ± 8) mm and (49 ± 9) mm postoperatively (t = 5.634, 5.885; P = 0.000). There was no significant change in ER group pre- and postoperatively ((51 ± 6) mm vs.(49 ± 7) mm, t = 1.524, P = 0.133). The patients with coronary artery disease and left ventricular dysfunction can benefit from surgical revascularization on different timing after STEMI, presenting as the reverse of left ventricle remodeling and the improvement of left ventricle function. The short-term results are mainly determined by the patients' condition, surgical technique and the level of perioperative management.It is recommended for this patient cohort to accept surgical revascularization three weeks after STEMI.

Abstract W P101: Surgical Revascularization Reverses Decreased Cerebral Oxygen Metabolism in Young Patients with Moyamoya Disease

Purpose: This prospective study was aimed to evaluate the effects of surgical revascularization on cerebral oxygen metabolism in moyamoya disease. Methods: This study included totally 41 patients who underwent STA-MCA anastomosis and indirect bypass for moyamoya disease between 2000 and 2011. There were 12 children and 29 adults. Totally 67 hemispheres underwent surgery. MR imaging and 15O-gas positron emission tomography (PET) were performed before and 3 to 4 months after surgery. Hemodynamic and metabolic parameters were precisely quantified. Results: Preoperative PET scans revealed that cerebral metabolic rate for oxygen (CMRO2) was kept normal in 15 hemispheres (22%), but decreased in other 52 (78%). The incidence did not differ between pediatric and adult patients. Pronounced cerebral ischemia was observed in all hemispheres with decreased CMRO2. After surgery, CMRO2 value significantly improved to the normal level in 20 (38%) of 52 hemispheres, but did not change in other 32 (62%). Multivariate analysis showed that the predictors for postoperative CMRO2 normalization were patient’s age (younger than 40 years) and no parenchymal damage on MRI. Conclusion: These findings strongly suggest that cerebral oxygen metabolism is often depressed in response to dense and chronic cerebral ischemia in moyamoya disease. The phenomenon may be advantageous to protect the involved hemispheres against ischemia. Surgical revascularization may readily normalize oxygen metabolism in young patients without any parenchymal damage.

Effect of surgical revascularization in patients with coronary artery disease and ventricular tachycardia or fibrillation in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Registry

Background Patients who undergo resuscitation from near-fatal ventricular arrhythmias often have significant coronary artery disease, and revascularization has been shown to reduce myocardial ischemia and cardiac arrest episodes in this patient population. The magnitude of benefit attributed to revascularization has varied by study, and the use of adjunct implantable cardioverter defibrillator (ICD) therapy has not been well-characterized. Methods and Results The Antiarrhythmics Versus Implantable Defibrillators (AVID) registry included 3117 patients with life-threatening ventricular arrhythmias, of whom 2321 (77%) had documented coronary artery disease and 281 (17%) underwent a coronary artery bypass grafting revascularization procedure after the index event. Patients who underwent a revascularization procedure were younger, had a lower incidence rate of prior myocardial infarction and ventricular arrhythmia, had a higher left ventricular ejection fraction, had less congestive heart failure, and were more likely to have had ventricular fibrillation as the presenting arrhythmia. Patients who underwent revascularization had a better survival rate than did those who did not undergo such a procedure after the index event, and adjustment for differing baseline patient covariates did not alter the relative survival rate benefit. Further, ICD implantation offered a similar survival rate advantage to those patients in the AVID registry with coronary artery disease independent of revascularization. Conclusion Coronary revascularization in the AVID registry patients with coronary artery disease effected a survival rate benefit that was not attributable to differences in baseline patient characteristics. The benefit of ICD on patient survival rate was not attenuated by a revascularization procedure. (Am Heart J 2002;143:821-6.)

Effects of Surgical Revascularization on Peripheral Artery Aneurysms in Moyamoya Disease: Report of Three Cases

Effects of Surgical Revascularization on Peripheral Artery Aneurysms in Moyamoya Disease: Report of Three Cases

Effects of surgical revascularization on outcome of patients with pediatric moyamoya disease.

We reviewed surgically treated patients with pediatric moyamoya disease and examined whether vasoreconstructive surgeries reduced the risk of recurrent ischemic attacks and changed overall outcomes in terms of the patients' performance and intellectual status. Sixty-four hemispheric sides in 34 pediatric moyamoya disease patients who received surgical treatment were examined. We performed superficial temporal artery to middle cerebral artery (STA-MCA) bypass and encephalo-duro-arterio-myo-synangiosis (EDAMS) on 48 sides (combined group) and indirect bypass surgery such as EDAMS on 16 sides (indirect group). These 34 patients were observed postoperatively from 1 to 14 years (mean +/- SD, 6.6 +/- 3.8 years) and were examined for the incidence of recurrent ischemic attack. Of the 34 patients, 23 were followed up for > 5 postoperative years, and their overall outcomes in terms of their performance and intellectual status were determined. Perioperative ischemic events (< or = 2 weeks after surgery) occurred in 5 surgeries (31%) of the indirect group and in 6 (13%) of the combined group (P = NS). The incidence of postoperative ischemic events (> 2 weeks after surgery) was significantly reduced in the combined group (10%) compared with the indirect group (56%; P < .01). Of the 23 patients observed > 5 years, 7 patients (30%) were mentally retarded and regarded as having a fair outcome. Combined surgery (STA-MCA bypass with EDAMS) for pediatric moyamoya disease was effective in reducing the risk of postoperative ischemic attacks compared with indirect surgery. Surgical revascularization may be effective in preventing intellectual deterioration and improving overall outcome.