Keita Kikuchi

Relationship between exercise tolerance and muscle strength following cardiac rehabilitation: Comparison of patients after cardiac surgery and patients with myocardial infarction

BACKGROUND AND PURPOSE Previous studies have demonstrated that cardiac rehabilitation (CR) improves exercise tolerance and muscle strength in patients with myocardial infarction (MI) and in patients after cardiac surgery. However, the association between exercise tolerance and muscular strength following CR and the comparison of relationships among various disease categories has not been fully examined. The purpose of the present study was to assess the relationship between exercise tolerance and muscle strength following CR in patients after cardiac surgery and patients with MI. METHODS AND RESULTS One hundred and four patients who participated in CR for 6 months were enrolled [post-cardiac valve surgery (VALVE), n=28; post-coronary artery bypass grafting (CABG), n=42; post-acute MI, n=34]. The exercise tolerance, thigh/calf circumferences, and muscle strength were measured before and after CR. At the baseline, the thigh circumference was significantly smaller in the VALVE group than in the MI group. There were significant positive correlations between peak VO(2) and muscle torques of the lower muscles in all groups. After 6 months, peak VO(2) and muscle torque were significantly increased in all groups (p<0.001). A positive significant correlation between percent increases in peak VO(2) and muscular strength was observed in the VALVE group (r=0.51, p<0.01), but not in the other groups. In addition, the changes in peak VO(2) and calf circumference after CR were significantly higher in the VALVE group than in the MI group. CONCLUSIONS These data suggest that exercise intolerance in patients after heart valve surgery may in part depend on decreased muscular strength. Further studies are needed to assess whether the strategy of increasing muscular strength of lower limb by programmed resistance training could be effective for improving exercise intolerance in patients after heart valve surgery and symptomatic patients with heart failure.

EuroSCORE predicts postoperative mortality, certain morbidities, and recovery time

EuroSCORE (European System for Cardiac Operative Risk Evaluation) used for calculating the risk of the postoperative mortality rate for patients undergoing open-heart surgery may be able to predict postoperative complications as well. Consecutive cases of isolated on-pump coronary artery bypass grafting (CABG) (n=1552) performed between 1991 and 2006 at our hospital group were placed into a systematic database. Patients were stratified using additive EuroSCORE. Incidence of postoperative mortality, morbidity (bleeding, heart failure, mediastinitis, pneumonia, myocardial infarction, renal failure, and stroke), and recovery time (intubation time, ICU stay, and postoperative length of stay) was assessed in each EuroSCORE group. EuroSCORE was well correlated with mortality, total incidence of major complications, heart failure, renal failure, stroke, pneumonia and mediastinitis, and three parameters of recovery time. Postoperative myocardial infarction and incidence of bleeding were not correlated with EuroSCORE. EuroSCORE can predict not only mortality but also postoperative complications and recovery time.

Metabolic syndrome is an independent risk factor for stroke and acute renal failure after coronary artery bypass grafting.

OBJECTIVES Metabolic syndrome is common among patients having coronary artery bypass grafting. However, it remains unclear whether it has a significant impact on postoperative complications. We aimed to determine whether metabolic syndrome negatively influences the postoperative outcomes of coronary artery bypass grafting. METHODS We enrolled 1183 patients who had coronary artery bypass grafting at Juntendo University Hospital between 1984 and 1992. Patients were categorized by the presence or absence of metabolic syndrome using the modified National Cholesterol Education Program Adult Treatment Panel III definition with body mass index in the place of waist circumference. Multivariate analysis was performed to assess the relationships between preoperative presence of metabolic syndrome and postoperative outcomes. RESULTS Metabolic syndrome was present in 551 (46.6%) patients and absent in 632 (53.4%). Postoperative stroke occurred in 4.7% of patients with metabolic syndrome and 2.1% of patients without metabolic syndrome (P < .0001). Postoperative acute renal failure occurred in 3.8% of patients with metabolic syndrome and 1.1% of patients without metabolic syndrome. On multivariate analysis, metabolic syndrome had odds ratios of 2.47 (95% confidence interval 1.22-4.99; P = .012) for postoperative stroke and 3.81 (95% confidence interval 1.42-10.3; P = .008) for postoperative acute renal failure. CONCLUSIONS This study showed the clinical importance of metabolic syndrome with respect to postoperative stroke and acute renal failure in patients having coronary artery bypass grafting. Like many established risk factors for postoperative complications, metabolic syndrome should be recognized as a novel risk factor for adverse events.

Off-pump minimally invasive coronary artery bypass grafting using the bilateral internal thoracic arteries and the right gastroepiproic artery

We report our initial experience of an off-pump total arterial minimally invasive coronary arterial bypass grafting (MICS CABG) with the use of bilateral internal thoracic arteries (BITA) and the right gastroepiproic artery. A 47-year old male with renal dysfunction secondary to diabetes mellitus was admitted for heart failure due to severe triple-vessel disease. Off-pump MICS CABG with total arterial grafts was elected because the patient refused to undergo median sternotomy due to the strong desire to regain the baseline function promptly. Total arterial grafts were selected to maximize the potential long-term outcome. There were no postoperative complications except temporary dialysis. Postoperative coronary computed tomography revealed the patency of all grafts. Our experience suggests that BITA can be safely harvested under direct vision in MICS CABG. Total arterial graft revascularization with BITA via minimally invasive approach may offer the benefits of MICS CABG while providing the undetermined but potentially superior conduit longevity of arterial grafts.

Perioperative outcomes of off-pump minimally invasive coronary artery bypass grafting with bilateral internal thoracic arteries under direct vision†

OBJECTIVES We previously introduced techniques to harvest and use the right internal thoracic artery in minimally invasive coronary artery bypass grafting (CABG) via a single left thoracotomy for revascularization with bilateral internal thoracic arteries (BITA). We report our short-term outcomes of patients who underwent minimally invasive CABG using BITA and a single internal thoracic artery (SITA). METHODS Consecutive patients who underwent minimally invasive CABG using BITA or SITA at a Japanese medical center between February 2012 and December 2015 were reviewed retrospectively. Preoperative, intraoperative and 30-day postoperative outcomes were analysed. Perioperative data for the SITA cohort is presented to provide a context in which the outcomes of the BITA cohort can be evaluated. RESULTS A total of 25 and 37 patients underwent BITA and SITA revascularization, respectively. The mean duration of the operation was longer in the BITA group than in the SITA group (265 ± 104 vs 336 ± 73 min). There were no deaths in the BITA group and one death in the SITA group. There were no strokes in either cohort, and new haemodialysis was required in one patient in each group. All BITA grafts were harvested without major complications and were all patent on computed tomography angiograms 1 week following the operations. CONCLUSIONS BITA can be safely harvested in a reproducible manner under direct vision via a small left thoracotomy. The potential advantages of minimally invasive CABG using BITA, although yet to be established, include a long-term survival benefit conferred by BITA grafts and elimination of the risk of sternal wound infection, in addition to the established advantages of minimally invasive coronary artery surgery. This approach has the potential for further optimization with hybrid revascularization strategies.

Skeletonization with an ultrasonic scalpel is as safe as a non-skeletonized dissection in preserving the endothelial function of the human gastroepiploic artery

The right gastroepiploic artery (GEA) is frequently used as another in situ artery, other than the internal thoracic artery (ITA) in coronary artery bypass grafting (CABG). Skeletonizing the graft with an ultrasonic scalpel is now regarded as a useful technique; however, this technique may damage the endothelial function during harvesting the graft resulting in postoperative graft stenosis or occlusion. In the present study, GEA segments from nine patients were excised in both a skeletonized and non-skeletonized manner with an ultrasonic scalpel, and then were transported to the laboratory. The vessels were trimmed as rings, and were allotted to the group of skeletonized or non-skeletonized, accordingly. The force development in response to 1 mumol/l norepinephrine did not differ between the skeletonized and non-skeletonized groups. Endothelium-dependent relaxation induced by either acetylcholine or bradykinin was not impaired in the skeletonized group in comparison to the non-skeletonized group. No significant difference was observed in endothelium-independent relaxation elicited by sodium nitroprusside. Therefore, the skeletonization of the GEA with an ultrasonic scalpel was thus found to be as safe as a non-skeletonized dissection in preserving the vascular contractile ability or endothelium-dependent and -independent relaxation of the graft.

The Use of Enclose ® II Anastomosis Assist Device for the Proximal Coronary Branch Anastomosis to Vascular Graft

We used the Enclose(®)II anastomosis assist device (Novare Surgical Systems, Inc., CA, USA), which was originally developed as an ancillary device for proximal anastomosis in off-pump coronary artery bypass grafting (OPCAB), to assist anastomosis for the vascular grafts without clamping those conduits in two cases. In these cases, it was difficult to clump vascular graft partially, because vascular graft was short. So we used Enclose(®)II anastomosis assist device for these cases. The advantage of this method is that the Enclose(®)II anastomosis assist device facilitates the anastomosis of arterial side branches to the artificial graft (1) by eliminating the use of partial clamp on the artificial conduits and (2) by providing a plane surface for easy handling for suture.

Should we consider surgical intervention for spinal cord ischemia due to acute type B aortic dissection

We present a 46-year-old man with a sudden onset of severe back pain following leg pain. An emergent computed tomography showed acute type B aortic dissection. The true lumen was almost completely occluded because of compression of a massive thrombus in the false lumen. The patient developed paraplegia by the time he was taken into the operation room. After induction of anesthesia, partial cardiopulmonary bypass was initiated, and then the chest was opened via left thoracotomy. The entry was found in the distal aortic arch and was successfully repaired. The descending aorta was replaced with a Dacron graft and antegrade re-perfusion was established in the descending aorta three hours after the onset of paraplegia. The patient recovered uneventfully without any neurological deficit. Paraplegia caused by acute type B aortic dissection is a rare complication. Usually it is treated medically. However, if the true lumen is occluded due to a massive thrombus in the false lumen, multiple malperfusion of the distal organs may occur. In such a case, surgical intervention should be considered to resume antegrade perfusion in the descending aorta as soon as possible.

Less-invasive coronary artery bypass grafting international landscape and progress

Purpose of review Less-invasive coronary artery bypass grafting (CABG) has evolved in multiple forms. Specifically noteworthy are recent technical refinement and reports of mid-term outcomes from well designed trials and observational studies in off-pump CABG, minimally invasive coronary artery bypass grafting (MICS CABG) and hybrid coronary revascularization (HCR). This review summarizes the historical evolution and recent development in less-invasive coronary artery bypass grafting. Recent findings A recent network meta-analysis of CABG with various degree of aortic manipulation demonstrated that no-touch technique may result in a significant reduction of postoperative stroke risk. A 5-year follow-up data of CORONARY study demonstrated that there was no significant difference in the rate of mortality, repeat revascularization, or primary composite outcome. The first multicenter observational study of HCR and PCI cohorts demonstrated that there was no significant difference in major adverse cardiac and cerebrovascular events at 12 months, with diverging event-free survival favoring HCR toward the end of the study period. Summary Less-invasive CABG continues to evolve in multiple forms. MICS CABG with the use of bilateral internal thoracic arteries preserves the sternum while allowing for a robust revascularization. HCR augments each form of less-invasive CABG, and is expected to play a larger role in the near future.

Vacuum-assisted closure with a portable system for treatment of poststernotomy mediastinitis

The patient was a 50-year-old man with diabetes who was on insulin. Complications of mediastinitis developed after coronary bypass surgery, which had been performed for unstable angina. Upon hospital admission, the patient was treated with antibiotics, and the wound was cleaned on a daily basis. However, because the patient’s fever persisted, the wound was completely opened surgically and found to be deep and large. Because the patient’s condition was relatively stable, minimally invasive vacuum-assisted closure was selected. We fabricated a portable vacuum-assisted closure system that imposed few limitations on individual movement. Vacuum-assisted closure treatment resulted in both rapid abatement of fever and improved granulation. Dressings were changed once a week; the wound was closed 4 weeks after vacuum-assisted closure and healed completely. Vacuum-assisted closure may be an effective therapy for postoperative mediastinitis, and our portable vacuum-assisted closure system may significantly reduce patient distress as well as direct medical care.