Coronary surgery in patients with peripheral vascular disease: effect of avoiding cardiopulmonary bypass

Off-Pump Coronary Artery Bypass Reduces Cardiac Death in Patients with Peripheral Arteriopathy

OBJECTIVE

 The aim of this study was to investigate whether the use of off-pump coronary artery bypass (OPCAB) may enhance early outcomes in subjects with peripheral artery disease (PAD) undergoing coronary artery bypass grafting (CABG).

METHODS

 We employed a propensity-score (PS) method to compare early postoperative results of OPCAB and on-pump CABG patients with associated PAD. The study population consisted of 1,961 patients: 284 in the OPCAB and 1,677 in the on-pump CABG group. The inverse probability of treatment weighting was used as PS method.

RESULTS

 The incidence of death (1.2% [95% confidence interval, CI: -0.9 to 3.3%], p = 0.262), stroke (2.2% [95% CI: -1.4 to 5.7%], p = 0.235), acute kidney disease (1.5% [95% CI: -3.8 to 6.8%], p = 0.586), limb ischemia (3.2% [95% CI: -0.6 to 7.0%], p = 0.315), and low output syndrome (1.2% [95% CI: -0.9 to 3.3%], p = 0.262) did not differ between the two groups. On the other hand, the rate of cardiac death (1.2% [95% CI: -0.1 to 2.3%], p = 0.038) was significantly higher in on-pump CABG group.

CONCLUSIONS

 The OPCAB procedure considerably reduced the occurrence of cardiac death after coronary revascularization. This finding might suggest that the OPCAB procedure should be considered as the first option in patients with higher cardiovascular risk scores. Further research is warranted.

The use of both internal thoracic arteries for coronary revascularization increases the estimate of post-operative lower limb ischemia in patients with peripheral artery disease

Background

Patients with a history of peripheral arterial disease (PAD) undergoing coronary artery bypass grafting (CABG) exhibit higher rates of complications. There are conflicting data on the survival benefits for bilateral thoracic artery (BITA) grafting compared with left internal thoracic artery (LITA) CABG in patients with PAD. The aim of the study was to explore the influence of the use of BITA grafts vs. LITA for CABG on post-operative acute lower limb ischemia (ALLI) and main post-operative complications in patients with concomitant PAD.

Methods

We used a propensity-score (PS) based analysis to compare outcomes between the two surgical procedures, BITA and LITA. The inverse probability of treatment weighting PS technique was applied to adjust for pre- and intra-operative confounders, and to get optimal balancing of the pre-operative data. The primary outcome was the estimate of postoperative ALLI. Secondary outcomes included overall death and death of cardiac causes within 30 days of surgery, stroke and acute kidney disease (AKD).

Results

The study population consisted of 1961 patients. The LITA procedure was performed in 1768 patients whereas 193 patients underwent a BITA technique. The estimate of ALLI was 14% higher in the BITA compared to the LITA (p < 0.001) group. Thirty-day mortality, cardiac death, occurrence of stroke and AKI did not differ significantly between the groups.

Conclusions

The use of both ITAs led to a significant increase in ALLI. This result was most likely caused by the complete disruption of the ITA collateral providing additional blood supply to the lower extremities. Based on our data, BITA should be used with extreme caution in PAD patients. Further research on this topic is necessary to confirm our findings.

Is Peripheral Artery Disease an Independent Predictor of Isolated Coronary Artery Bypass Outcome?

AIM

The aim was to use a propensity score-based analysis to determine the impact of peripheral artery disease (PAD) on early outcomes after coronary artery bypass surgery grafting (CABG) in patients with PAD.

METHOD

We conducted a multicentre retrospective analysis of 11,311 consecutive patients who underwent CABG between 1997 and 2017. Patients with previous or concomitant vascular surgery were excluded. The main endpoints were death, stroke, and limb ischaemia requiring percutaneous or surgical revascularisation. Subgroup analyses were performed to test the interaction of PAD with concomitant factors.

RESULTS

There was no difference in mortality in patients with and without PAD (p=0.06 and p=0.179, respectively). Patients with PAD had a greater incidence of stroke (p=0.04), acute kidney disease (p=0.003), and limb ischaemia requiring interventions (p<0.001) than those without PAD. The use of off-pump or no-touch aortic techniques did not influence the effect of PAD on the outcomes. Early mortality rate increased in patients with PAD when associated with long cardiopulmonary bypass, cross-clamp times (both p<0.001), and postoperative low cardiac output (p=0.01).

CONCLUSIONS

The presence of PAD is associated, independently of other factors, with greater incidence of stroke, acute kidney disease, and limb ischaemia following CABG, irrespective of the technique employed. Operative mortality was greater in patients with PAD only when associated with long cardiopulmonary bypass and aortic cross-clamp times, and low cardiac output.

Delayed hyperbaric oxygen therapy for air emboli after open heart surgery: case report and review of a success story

Background

The current case describes a rare diagnosis of iatrogenic air emboli after elective cardiopulmonary bypass that was successfully treated with delayed hyperbaric oxygen therapy, with good clinical evolution in spite of rare complications.

Case presentation

A 35 years old male was admitted to the intensive care unit (ICU) for post-operative management after being placed on cardiopulmonary bypass (CPB) for an elective ventricular septal defect closure and aortic valvuloplasty. The patient initially presented with pathologically late awakening and was extubated 17 h after admission. Neurologic clinical status after extubation showed global aphasia, mental slowness and spatio-temporal disorientation. The injected cerebral CT scan was normal; the EEG was inconclusive (it showed metabolic encephalopathy without epileptic activity); and the cerebral MRI done 48 h after surgery showed multiple small subcortical acute ischemic lesions, mainly on the left fronto- parieto- temporo-occipital lobes. He was taken for hyperbaric oxygen therapy (HOT) over 54 h after cardiac surgery. The first session ended abruptly after 20 min when the patient suffered a generalised tonico-clonic seizure, necessitating a moderately rapid decompression, airway management, and antiepileptic treatment. In total, the patient received 7 HOT sessions over 6 days. He demonstrated full neurological recovery at 4 weeks and GOS (Glasgow Outcome Scale) of 5 out of 5 even after a long delay in initial management. Convulsions are a rare complication of HOT either due to reperfusion syndrome or hyperoxic toxicity and can be managed. Prior imaging by MRI or tympanic paracentesis (myringotomy) should not add further delay of treatment.

Conclusion

HOT should be initiated upon late awakening and/or neurologic symptoms after CPB heart surgery, after exclusion of formal counter-indications, even if the delay exceeds 48 h.

Stroke associated with coronary artery bypass grafting

While coronary artery bypass grafting (CABG) has been playing a significant role in the revascularization for ischemic heart disease, neurological complications associated with CABG have been a primary concern. Stroke, although the incidence is low, is one of the most devastating complication of CABG. Many studies have identified the risk factors for stroke with CABG, such as prior stroke, carotid artery stenosis, aortic atherosclerosis, atrial fibrillation and cardiopulmonary bypass. Various rational approaches focusing on individual risk factor have been proposed for the stroke. Prophylactic carotid revascularization is an important strategy, and the diagnosis of carotid stenosis has to be established correctly. Prevention of emboli from aortic plaque is also an essential issue. Intraoperative monitoring with transesophageal or epiaortic ultrasound is useful to identify mobile atheromatous plaques and to select appropriate aortic manipulations. Maintenance of cerebral blood flow and blood pressure during cardiopulmonary bypass might be critical issues. Besides, there are conflicting two opinions regarding off-pump CABG; one supports an efficiency for the prevention of stroke while the other advocates no effect. This discrepancy might be explained by the difference of the risk of stroke in the population of the individual study and by the variation of the percentage of aortic clamping or aortic anastomosis in each study. Pharmaceutical therapies such as statin, preventive medication for atrial fibrillation, or antiplatelet are promising methods. Although it is hard to decrease the incidence of the stroke with any single countermeasure, sustained effort should be continued to overcome the stroke associated with CABG.

Hyperbaric Oxygen Therapy in the Treatment of Post Cardiac Surgical Strokes – a Case Series and Review of the Literature

Strokes remain an uncommon but significant complication of cardiac surgery. Cerebral air embolism is the likely aetiology in the majority of cases. Hyperbaric oxygen therapy is the recognised treatment for cerebral air embolism associated with compressed air (SCUBA) diving accidents and is therefore also the standard of care for iatrogenic causes of air embolism. It follows that there is a logic in treating post-cardiac surgical stroke patients with hyperbaric oxygen.

The aim of this retrospective review was to examine the outcomes of 12 such patients treated in the Christchurch Hospital hyperbaric unit and to appraise the evidence base for the use of hyperbaric oxygen therapy in this setting.

Despite delays of up to 48 hours following surgery before the institution of hyperbaric oxygen therapy, 10 of the 12 patients made a full neurological recovery or were left with mild residual symptoms, with nine returning to their previous level of care. One patient remained hemiplegic and there was one early neurological death.

There is a paucity of prospective data in this area, but based on sound pathophysiological principles and clinical experience, we believe that patients suffering a stroke following open cardiac surgery should be considered for hyperbaric oxygen therapy.

Anaortic techniques reduce neurological morbidity after off-pump coronary artery bypass surgery

BACKGROUND

Stroke remains one of the most devastating complications of cardiac surgery. Advocates of off-pump coronary revascularisation (OPCAB) maintain that post-operative neurologic morbidity is reduced by avoiding aortic cannulation and cross-clamping, and by eliminating the systemic effects of cardiopulmonary bypass. We sought to determine whether completing off-pump coronary surgery without any aortic manipulation ("anaortic" technique) afforded any additional neurological protection, as compared to off-pump grafting in which the aorta was utilised for graft inflow.

METHODS

A comprehensive review of prospectively collected data was undertaken of all patients undergoing OPCAB in our institution between January 2002 and December 2006. Cases requiring intra-operative conversion to cardiopulmonary bypass were excluded from further analysis. Patients having OPCAB surgery with aortic manipulation were compared to those having OPCAB surgery without aortic manipulation. Multiple logistic regression was used to identify possible predictors of post-operative neurologic morbidity, with particular focus on the role of aortic manipulation.

RESULTS

During the period of review, 1758 patients underwent OPCAB, of which 1201 (68.3%) were completed without aortic manipulation, constituting the "anaortic" cohort. This group was compared with the remaining 557 patients, which included fashioning at least one aorto-conduit anastomosis, utilising either a side-biting aortic clamp or a no-clamp proximal anastomotic device. The two groups of patients were well-matched with respect to risk factors for adverse neurologic outcomes. Nine patients sustained focal neurological deficits (transient or permanent) in the peri-operative period, constituting a stroke rate of 0.51% for the entire series. The incidence of peri-operative neurological deficit in the anaortic group was 0.25% compared with 1.1% in the aortic manipulation group (odds ratio (OR) 0.23, 95% confidence interval (CI) 0.06-0.92, p=0.037). Advanced age was also associated with peri-operative neurological injury (OR 1.1, 95% CI 1.01-1.20, p=0.017).

CONCLUSIONS

Off-pump coronary artery surgery is associated with a low incidence of peri-operative stroke. Completing the surgical procedure without manipulating the ascending aorta in any way ("anaortic" technique) offers additional neurological protection and should be the goal in all suitable off-pump coronary cases.

Revascularization with off-pump coronary artery surgery: what appears new is actually the old rediscovered

The enormous progress in interventional cardiology during the last 10 years has resulted in a major change in the spectrum of patients referred for coronary artery bypass grafting. Several large retrospective analyses, meta-analyses, and the randomized trials that addressed different aspects of ONCAB and OPCAB to date have compared the two surgical strategies. It is suggested that patients may achieve an excellent outcome with either type of procedure, and individuals' outcomes more likely depend on factors other than whether they underwent ONCAB or OPCAB. Nevertheless, there appear to be trends in most studies. These trends include less blood loss and need for transfusion, less myocardial enzyme release up to 24 h, less early neurocognitive dysfunction, and less renal insufficiency after OPCAB and propensity to lower costs, thereafter proving OPCAB to be safe and clinically effective. Here, we review the physiological advantages and clinical outcomes of OPCAB for myocardial revascularization and examine whether either strategy is superior and in which patients.

Living with off-pump coronary artery surgery: evolution, development, and clinical potential for coronary heart disease patients

The enormous progress in interventional cardiology during the last 10 years has resulted in a major change in the spectrum of patients referred for coronary bypass surgery. These patients are older and sicker and frequently have had previous percutaneous coronary interventions. Consequently, cardiac surgery is responding by adding new surgical techniques: off-pump open-chest coronary bypass surgery (OPCAB), minithoracotomy bypass surgery, videothoracoscopic (robotic) procedures, etc. Several registries published to date have proved OPCAB to be safe and clinically effective. Randomized studies and meta-analysis research in this field provide scientific support and suggest that myocardial, renal, and neurological functions, amongst others, are better preserved by OPCAB than by classic techniques that use a cardiopulmonary bypass pump (CPB). Moreover, avoidance of CPB yields significantly reduced oxidative stress and systemic inflammatory response. This results in higher safety for ischemic heart disease patients undergoing revascularization, thus offsetting the propensity to lower costs. The present review examines the physiological advantages and clinical outcomes of this simple mode of myocardial revascularisation and evaluates the wider implications arising from its evolution.