Minimizing the risk of perioperative stroke by clampless off-pump bypass surgery: a retrospective observational analysis

The brain-before-heart strategy for coronary artery bypass grafting in the severely atherosclerotic aorta: A single-institution experience

BACKGROUND

Severe atherosclerosis of the ascending aorta (SAA) in patients undergoing surgical revascularization by coronary artery bypass grafting (CABG) is becoming an increasing problem as more elderly patients are diagnosed with coronary artery disease. Strokes and other neurologic insults are common complications in this group, with devastating impacts on outcomes and prognoses.

HYPOTHESIS

Early detection of the atherosclerotic aorta and the application of a stroke prevention protocol will reduce the risk of stroke in patients with SAA.

METHODS

In 2012, we adopted a protocol devised to preemptively detect and manage patients suspected of having SAA. From the time of the application of the protocol, we compared the immediate and late outcomes of CABG in SAA in the 8 years preceding the protocol in a "control" group (30 patients) and in the 8 years following the protocol in a "brain" group (69 patients).

RESULTS

More patients with SAA were detected after the initiation of the protocol. They had significantly more history of stroke, renal dysfunction, and left main coronary disease. The percutaneous coronary intervention was utilized more after the protocol (26% vs. 7%) and there was far less utilization of replacement of the ascending aorta (12% vs. 37%). Postoperative stroke rates were significantly less after the protocol (2% vs. 18%), with an almost twofold reduction in stroke associated with SAA even after risk adjustment. The composite endpoints of cardiac death, nonfatal myocardial infarction, and stroke were significantly reduced after initiating the protocol at a median of 2.3 years from the time of revascularization.

CONCLUSION

Early detection of SAA and individualized therapeutic strategies for revascularization is effective in reducing athero-embolic brain injury and are associated with better prognosis.

Surgical strategies for severely atherosclerotic (porcelain) aorta during coronary artery bypass grafting

Porcelain aorta (PA) is an asymptomatic atherosclerotic disease, characterized by circumferential calcification throughout the whole perimeter of the aorta. It is seen in 2% to 9.3% of patients undergoing elective coronary artery bypass grafting (CABG) and makes manipulation of the ascending aorta impossible. It has been clearly shown that most emboli seen and detected during the CABG procedure occur during aortic cross-clamping and aortic side-clamping. Manipulation of porcelain or a severely atherosclerotic aorta increases the risk of perioperative stroke. The incidence of stroke after CABG is between 0.48% and 2.9%, and the risk is correlated with the extent and severity of the atherosclerotic disease. A conventional CABG procedure involves successive steps that include cannulation of the ascending aorta, application of a cross-clamp to the aorta, and partial clamping of the aorta to create the proximal anastomosis. Therefore in procedures that involve cannulation, clamping, or proximal anastomosis, and where aortic manipulation is inevitable, preassessment of the atherosclerotic aortic plaques is crucial. Although many surgeons still rely on intraoperative manual aortic palpation, this approach has very low sensitivity and underestimates the severity of the atherosclerotic illness. Imaging methods including preoperative computed tomography or intraoperative epiaortic ultrasonography enable modification of the surgical technique according to the severity of atherosclerosis. Various surgical techniques have been described to reduce the risk of atheroembolism that may lead to cerebrovascular events in patients with severely atherosclerotic ascending aorta. Anaortic or "no-touch" techniques that do not utilize aortic manipulation may significantly decrease the development of neurological complications by avoiding aortic maneuvers known to cause emboli. In cases where severe atherosclerotic disease or other factors preclude safe use of the ascending aorta, modifications in the surgical techniques, such as switching to different cannulation sites including the axillary/subclavian, femoral and innominate arteries, or using hypothermic ventricular fibrillation and in-situ pedicled arterial grafts, or performing proximal anastomoses at alternative anatomical locations will enable CABG operations to be performed safely with low morbidity and mortality rates in patients with porcelain aortas.

Incidence of perioperative stroke in clampless aortic anastomosis during off-pump coronary artery bypass grafting

This study aimed to assess if clampless off-pump coronary artery bypass grafting (OPCAB) decreases the incidence of perioperative stroke (POS) rate and in-hospital mortality. The secondary aim was to evaluate 12-year rates of overall mortality. Between January 2003 to December 2015, data of 645 consecutive patients undergoing isolated CABG were retrospectively collected. 363 underwent aortic no-touch OPCAB (No-touch group) and 282 underwent OPCAB with the Heartstring device (HS group). In-hospital mortality and perioperative stroke rate as primary endpoint, as well as long-term follow-up outcome were analysed. In-hospital mortality was lower into No-touch group compared with HS group but without significant statistical difference (1.7 vs. 3.2%, p = 0.19, respectively); the rate of postoperative stroke was higher in No-touch group compared with HS group, although this difference did not reach statistically significance. Delirium was reported with higher presentation rate in HS group (3.9 vs. 0.8%, p = 0.01). Blood transfusions rate was higher in HS subjects (23.4 vs. 16.1%, p = 0.01). Intubation time, ICU, and hospital length of stay were increased in the HS group (p = 0.008, p = 0.001 and p = 0.003, respectively). Over a 12-year follow-up period, survival probabilities at 1, 5, and 10 years were 93.6 ± 1.3 vs. 93.2 ± 1.5, 80.4 ± 2.6 vs. 80.3 ± 2.2, and 57.9 ± 5 vs. 58.4 ± 3.8% in the No-touch and HS group, respectively (p = 0.97). In this retrospective study, clampless off-pump CABG lowers perioperative stroke rate whose incidence is, however, not inferior compared with No-touch technique, and no statistically significance was detected. Delirium has a higher presentation rate in clampless off-pump CABG.

Acute Kidney Injury in Cardiac Surgery and Cardiac Intensive Care

Acute kidney injury (AKI) is a serious postoperative complication following cardiac surgery. Despite the incidence of AKI requiring temporary renal replacement therapy being low, it is nonetheless associated with high morbidity and mortality. Therefore, preventing AKI associated with cardiac surgery can dramatically improve outcomes in these patients. The pathogenesis of AKI is multifactorial and many attempts to prevent or treat renal injury have been met with limited success. In this article, we will discuss the incidence and risk factors for cardiac surgery associated AKI, including the pathophysiology, potential biomarkers of injury, and treatment modalities.

Incidence of postoperative stroke using the Heartstring device in 1,380 coronary artery bypass graft patients with mild to severe atherosclerosis of the ascending aorta

BACKGROUND

Atherosclerotic disease of the ascending aorta during coronary artery bypass graft surgery (CABG) increases the risk for postoperative stroke. The objective of this study was to examine the incidence of postoperative stroke in CABG utilizing the Heartstring (Maquet Cardiovascular, San Jose, CA) proximal anastomotic device.

METHODS

Intraoperative epiaortic ultrasonography was used to grade atherosclerosis in CABG patients at Emory University from April 2003 to December 2012. The Heartstring device was utilized in 1,380 patients: 407 (29.5%) grade I (minimal atherosclerosis), 367 (26.6%) grade II, 437 (31.7%) grade III, 110 (8.0%) grade IV, and 59 (4.3%) grade V (severe atherosclerosis). Logistic regression analysis was used to estimate the effect of aortic grade on outcomes adjusted for Society of Thoracic Surgeons predicted risk of mortality and predicted risk of stroke scores.

RESULTS

The mean age of all patients was 66.7 ± 10.5 years, and 31.9% were female. An increasing risk profile was apparent with rising aortic grade. Most CABG was done off pump (n = 1,277, 92.5%). There was no significant association between aortic grade and frequency of postoperative stroke (p = 0.83). In all patients, use of the Heartstring device reduced the predicted risk of stroke by 44% (O:E risk 0.56). The benefit for postoperative stroke was least apparent in the grade I aorta patients (O:E 0.8) compared with patients having grade II and greater. There were no strokes among patients with severe atherosclerosis using the Heartstring device.

CONCLUSIONS

Compared with the Society of Thoracic Surgeons predicted risk for stroke, the Heartstring proximal anastomotic device can be safely used with all aortic grades. The most prominent benefit appears to be for patients with grade II disease and greater.

Impact of cardiopulmonary bypass on acute kidney injury following coronary artery bypass grafting: a matched pair analysis

BACKGROUND

Postoperative Acute Kidney Injury (AKI) after coronary artery bypass grafting (CABG) is a common complication associated with significant morbidity and mortality. Cardiopulmonary bypass (CPB) is accepted to contribute to the occurrence of AKI and is of particular importance as it can be avoided by using the off-pump technique. However the renoprotective properties of off-pump (CABG) are controversial. This analysis evaluates the impact of cardiopulmonary bypass on renal function.

METHODS

A matched-pair analysis of 1428 patients undergoing coronary artery bypass grafting was conducted. The patients were stratified according to their preoperative renal function and to risk factors for postoperative AKI. The development of the glomerular filtration rate (GFR) from before surgery until hospital discharge was analyzed. Incidence of AKI were analyzed. Furthermore the impact of CPB duration on postoperative GFR was assessed.

RESULTS

The occurrence of AKI increases the risk of thirty-day mortality (odds ratio of 4.3). The postoperative GFR decreases significantly after coronary artery bypass grafting but does not differ between onpump and offpump CABG (60.2 ± 24.5 vs 60.7 ± 24.8; p=0.54). No difference regarding the incidence (26.6% vs 25%) and severity of AKI between cardiopulmonary bypass and the off-pump technique could be found. Duration of cardiopulmonary bypass does not correlate with the decline in postoperative glomerular filtration rate (Pearson Product Moment Correlation; p>0.050).

CONCLUSION

Neither the mere use nor duration of cardiopulmonary bypass proofed to be a risk factor for developing postoperative AKI in CABG patients with a comparable preoperative risk profile for postoperative renal dysfunction. Furthermore, the severity of postoperative AKI is not affected by the use of cardiopulmonary bypass.

Anastomotic devices in coronary artery surgery: it is about the anastomosis?

Excellent long-term graft patency remains the primary goal of any surgical coronary revascularization procedure, irrespective of how the operation itself is performed. Inter- and intra-surgeon variability in the surgical technique and in the subsequent quality of the anastomosis have the potential to significantly impact not only on graft patency but also, as a result, on patient outcomes. Anastomotic devices, proximal and distal, can facilitate the creation of rapid, reproducible, compliant anastomoses, on- or off-pump, in potentially difficult-to-access areas, often through minimal-access incisions, potentially with neuro-protective benefits, and can thus mitigate some of the hazards inherent in manually constructing anastomoses in technically challenging or suboptimal conditions. We review the three most commonly employed anastomotic devices in adult cardiac surgical practice today.

HEARTSTRING enabled no-touch proximal anastomosis for off-pump coronary artery bypass grafting: current evidence and technique

Surgical revascularization remains the standard of care for many patients. Off-pump coronary artery bypass grafting (OPCAB) without cardiopulmonary bypass (CPB) has evolved during the past 20 years, and as such can significantly reduce the occurrence of neurological complications. While avoiding the aortic cross-clamping required in conventional on-pump techniques, OPCAB results in a lower incidence of stroke. However, clamp-related risk of stroke remains if partial or side-biting clamps are applied for proximal anastomoses. Others and we have demonstrated that no-touch 'anaortic' approaches avoiding any clamping during off-pump procedures via complete in situ grafting result in significantly reduced stroke rates when compared with partial clamping. Therefore, OPCAB in situ grafting has been proposed as the 'standard of care' to reduce neurological complications. However, this technique may not be applicable to for every patient as the use of free grafts (arterial or venous) requiring proximal anastomosis is often still necessary to achieve complete revascularization. In these situations, proximal anastomosis can be performed without a partial clamp by using the HEARTSTRING device, and over the last few years, considerable evidence has arisen supporting the impact of HEARTSTRING-enabled anastomosis to significantly minimize atheroembolism and neurological complications when compared with partial- or side-bite clamping. This paper provides a systematic overview and technical information about the combination of OPCAB and clampless strategies using the HEARTSTRING for proximal anastomosis to reduce stroke to levels reported for percutaneous coronary intervention.

Clampless technique during coronary artery bypass grafting for proximal anastomoses in the hostile aorta

OBJECTIVE

The incidence of stroke in patients undergoing coronary artery bypass grafting increases sharply in the face of significant atherosclerotic disease of the ascending aorta. We use a technique that allows full revascularization for this cohort of patients, while minimizing cerebral embolic risk.

METHODS

Intraoperative epiaortic ultrasound was used to screen for moderate or severe atherosclerotic disease of the ascending aorta and to precisely identify safe areas for cannulation and proximal anastomoses. By using a mildly hypothermic fibrillating technique, distal revascularization was then performed without clamping the aorta. Proximal anastomoses were accomplished under brief periods of circulatory arrest.

RESULTS

We routinely use this technique and examined our results in 71 consecutive patients found to have grade 3 or greater atherosclerotic plaque of the ascending aorta. This represented approximately 10.0% of our total population who underwent coronary artery bypass grafting over a 32-month period from January 2007 to September 2009. One patient (1.4%) had a mild stroke that resolved, and there were no other neurologic complications.

CONCLUSIONS

We have found that clampless fibrillating heart surgery with circulatory arrest for proximal anastomoses is a safe and effective technique for revascularizing patients with significant ascending aortic disease who are at high risk for cerebral embolic complications.

Ondasetron versus haloperidol for the treatment of postcardiotomy delirium: a prospective, randomized, double-blinded study

Background

To investigate the controlling efficacy of ondasetron and haloperidol in regard to the postcardiotomy delirium.

Methods

We included in this prospective, randomized, double-blinded study 80 patients who developed delirium after heart surgery with the application of heart lung-machine. The patients were divided into two, equally-sized groups, which on detection of delirium received ondasetron 8 mg iv or haloperidol 5 mg iv respectively. The statistical analysis compared the baseline and demographic characteristics of the two groups (age, gender, comorbidities, years of education, type of surgery etc.).

Results

Both ondasetron and haloperidol had very good delirium controlling effects, without statistically significant differences.

Discussion-Conclusions

Ondasetron and haloperidol are efficient agents as far as the treatment of postcardiotomy delirium is concerned. As, in addition, ondasetron bares milder side-effects, we believe this could be the agent of choice in patients developing postcardiotomy delirium in the future.

Avoiding the clamp during off-pump coronary artery bypass reduces cerebral embolic events: results of a prospective randomized trial

The purpose of this study was to determine whether a clampless facilitating device (CFD) to perform proximal aortocoronary anastomoses would result in a lower incidence of cerebral embolic events compared with a partial clamping strategy during off-pump coronary artery bypass (OPCAB). After epiaortic ultrasound confirmed the mild aortic disease (Grades I and II), 57 patients were randomly assigned to have proximal anastomoses using a partial-occluding clamp (CL, n = 28) or a CFD [Heartstring (HS), n = 29] (Maquet Cardiovascular LLC, San Jose, CA). Solid and gaseous emboli in the middle cerebral arteries were detected using transcranial Doppler ultrasonography. The mean number of proximal anastomoses was similar between groups 1.93 ± 0.72 (CL) and 1.72 ± 0.70 (HS) (P = 0.28). The mean number of gaseous plus solid emboli was greater in the CL group than the HS group (90.0 ± 64.0 vs. 50.8 ± 36.6, P = 0.01). Emboli were fewest in patients undergoing HS anastomoses using the suction device. The number of intraoperative cerebral emboli was proportional to the number of proximal anastomoses in the HS groups, but independent of the number of proximal anastomoses in the CL groups. Among patients with a low burden of aortic atherosclerosis, partial clamping of the ascending aorta during OPCAB was associated with more cerebral embolic events compared with an anastomosis with a CFD.

Aortic no-touch technique makes the difference in off-pump coronary artery bypass grafting

OBJECTIVES

Both off-pump surgery (OPCAB) and aortic no-touch technique reduce stroke after coronary artery bypass grafting (CABG). We evaluate the impact of partial aortic clamping (PC) versus a no-touch technique using either the HEARTSTRING system (HS) or total arterial revascularization (TAR) on the incidence of stroke.

METHODS

From 1999 [corrected] to 2009, 4314 patients underwent myocardial revascularization. Patients either underwent OPCAB (n = 2203) or conventional on-pump CABG (n = 2111). The OPCAB cohort was divided into 2 subgroups: patients requiring proximal anastomosis applying PC (n = 567) or a "no-touch" technique with the HS (n = 1365). Patients who received TAR (n = 271) served as a control group (gold-standard). Data collection was performed prospectively using a propensity score (PS)-adjusted regression analysis. End points were stroke, mortality, major adverse cardiac and cerebrovascular events (MACCE), and a noncardiac composite end point including respiratory failure, renal failure, and bleeding.

RESULTS

The mortality rate (1.6% vs 2.4%; propensity-adjusted odds ratio [PAOR] = 0.51; CI 95%, 0.26-0.99; P = .047), MACCE (7.9% vs 17.1%; PAOR = 0.67; CI 95%, 0.52-0.84; P = .001) including myocardial infarction (1.1% vs 2.2%; PAOR = 0.50; CI 95%, 0.26-0.98; P = .044) and stroke (1.1% vs 2.4%; PAOR = 0.35; CI 95%, 0.17-0.72; P = .005) as well as the noncardiac composite (PAOR = 0.46; CI 95%, 0.35-0.91; P < .001) were significantly lower for OPCAB when compared with on-pump CABG. In comparison with PC, OPCAB patients undergoing the HS approach had significantly lower frequencies of stroke (0.7% vs 2.3%; PAOR = 0.39; CI 95%, 0.16-0.90; P = .04) and MACCE (6.7% vs 10.8%; PAOR = 0.55; CI 95%, 0.38-0.79; P = .001), and these results were similar to those of the control group, who underwent no-touch TAR (stroke rate, 0.8%; MACCE, 7.9%).

CONCLUSIONS

Our results confirm that OPCAB is superior with regard to risk-adjusted outcomes. There is no difference in the stroke rate when comparing on-pump CABG versus applying partial aortic crossclamping in OPCAB. Whenever a proximal anastomosis is needed, a no-touch technique should be applied, that is, using the HS device.

Myocardial revascularization without extracorporeal circulation in patients at high operative risk

It is considered that over 25% of surgical patients with coronary artery disease are treated without extracorporeal circulation, i.e. off-pump coronary artery bypass. The aim of the study was to evaluate results of surgical myocardium revascularization in patients at high operative risk. During the period 2005-2008, 148 patients were operated without the use of extracorporeal ciruculation. According to the logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) stratification, 28 patients (19%) were designated as the high risk patients. The average age of these high risk patients was 72 years (55-86). The group consisted of 23 men (82.1%) and 5 women (17.8%). The postoperative mortality in the whole group of patients was 0.68% (1/148), whereas it was 0% in the high risk group. The average number of coronary anastomoses was 2.4. Eight patients (28.6%) had some sort of postoperative complications. Our results demonstrate safety and efficacy of surgical revascularization without cardiopulmonary bypass in patients at high operative risk.

Meta-analysis on the use of the Heartstring anastomotic device to prevent stroke in patients undergoing off-pump coronary artery bypass grafting

OBJECTIVE

Postoperative stroke is the Achilles' heel of coronary artery bypass surgery compared with percutaneous coronary intervention. In this meta-analysis, we sought to determine the efficacy of the Heartstring proximal anastomotic device to reduce the risk of postoperative stroke after off-pump coronary artery bypass grafting (OPCAB).

METHODS

Studies on the Heartstring device were identified by searching PubMed, Cochrane Library and Scopus up to November 2010. The results were expressed as pooled proportions (%) with 95% confidence interval (95% CI). Heterogeneity across the studies was evaluated by the I(2) test and a random effects model was used.

RESULTS

Eighteen articles were pertinent with this issue and we were able to retrieve data on the Heartstring anastomotic device in OPCAB from eight studies. Three studies were prospective and routine epi-aortic ultrasound was used in three studies. A total of 819 patients were enrolled in these eight studies and six of them suffered stroke postoperatively. Cumulative analysis showed a pooled rate of immediate postoperative stroke after OPCAB with the use of Heartstring of 1.9% (95% CI 0.8-4.5, I(2)=23%). Sensitivity analysis including the only three studies evaluating patients with diseased ascending aorta as detected at epi-aortic ultrasound showed that a pooled rate of stroke was 3.2% (95% CI 0.8-11.9, I(2)=0%). Six studies reported on immediate postoperative mortality and the pooled mortality rate was 1.9% (95% CI 0.1-3.4).

CONCLUSIONS

The results of this meta-analysis suggest that the risk of stroke after OPCAB may not be markedly reduced by the use of Heartstring device. On the other hand, a rather low rate of stroke was observed among patients with diseased ascending aorta indicating its potential value in these patients. Most of studies included in this meta-analysis were of poor methodological quality, and properly conducted prospective studies are needed to get more conclusive results on the safety and efficacy of Heartstring anastomosis device.