Routine Off-Pump Coronary Artery Bypass Grafting Is Safe and Feasible in High-Risk Patients With Left Main Disease

Matched Analysis of Surgical versus Percutaneous Revascularization for Left Main Coronary Disease

BACKGROUND

Percutaneous coronary intervention (PCI) is being performed more frequently for left main coronary artery disease (LMCAD). This study evaluated a real-world propensity-matched analysis of surgical versus percutaneous revascularization for LMCAD.

METHODS

Adults (≥18 years) at a single academic institution undergoing coronary artery bypass grafting (CABG) or PCI for left main stenosis ≥50% between 2010-2018 were examined. Greedy propensity-matching techniques were used to generate well-matched cohorts, and Kaplan-Meier analysis was used to compare survival. Multivariable Cox models were created for 5-year mortality and major adverse cardiac and cerebrovascular events (MACCE).

RESULTS

1091 with LMCAD were identified (898 CABG, 193 PCI). Patients undergoing PCI were significantly older (77 vs 68 years, p<0.001), more likely to have heart failure (26.94% vs 13.14%, p<0.001), and were less likely to have 3-vessel disease (42.49% vs 65.59%, p<0.001). Propensity-matching yielded 215 CABG and 134 PCI well-matched patients. In the matched analysis, 1-year (77.61% vs 88.37%) and 5-year (48.77% vs 75.62%) survival were lower with PCI. Rates of MACCE at 5-years were also higher with PCI (64.93% vs 32.56%, p<0.001). Rates of both myocardial infarction (19.40% vs 7.44%, p=0.001) and repeat revascularization (26.12% vs 7.91%, p<0.001) were higher with PCI. Following risk adjustment, CABG remained associated with reduced risk of mortality (HR 0.40, 95% CI 0.29-0.54; p<0.001) and MACCE (HR 0.37, 95% CI 0.28-0.48; p<0.001) at 5 years.

CONCLUSIONS

This real-world, propensity-matched analysis demonstrates substantial advantages in survival and MACCE with CABG for LMCAD, supporting surgical revascularization in this clinical setting in appropriate operative candidates.

Prophylactic intra-aortic balloon pump in patients with left main disease undergoing off-pump coronary artery bypass grafting

Background

Preventive intra-aortic balloon pump (IABP) for high-risk patients with stable hemodynamics is controversial, and its definition of high-risk is still unclear. This study aimed to investigate the effect of prophylactic IABP on the early outcome of left main disease (LMD) patients receiving off-pump coronary artery bypass grafting (OPCABG) with stable hemodynamics.

Methods

From January 2013 to April 2020, 257 consecutive patients who underwent OPCABG through sternotomy were enrolled in this study. All LMD patients (greater than 70%) had stable hemodynamics (BP>100 mmHg without vasoconstrictor substance infusion). Early outcomes of 125 patients with prophylactic IABP (IABP group) and 132 patients without IABP (Control group) were compared in this study.

Results

IABP did not show favorable effect on the conversion to CPB (RR 0.63, 95%CI 0.05–7.89, P = 0.7211), perioperative MI (RR 0.69, 95%CI 0.22–2.12, P = 0.5163), mortality (RR 0.65, 95%CI 0.04–10.25, P = 0.7608) or the composite end of the conversion, MI and mortality (RR 0.63, 95%CI 0.23–1.74, P = 0.3747). There was greater incidence of prolonged ventilation in IABP after adjustment (RR2.16, 95%CI 1.12–4.18, P = 0.0221). There was no IABP-related mortality or limb ischemia.

Conclusion

No significant difference in early outcomes was observed in hemodynamically stable patients with LMD between prophylactic IABP group and control group. Prophylactic IABP may be unnecessary in patients with LMD undergoing OPCABG.

Emergency Coronary Artery Bypass Grafting: Indications and Outcomes from 2003 through 2013

Emergency coronary artery bypass grafting (CABG) is associated with increased in-hospital mortality rates and adverse events. This study retrospectively evaluated indications and outcomes in patients who underwent emergency CABG. The Society of Thoracic Surgeons database for a single center (Jewish Hospital) was queried to identify patients undergoing isolated CABG. Univariate analysis was performed. From January 2003 through December 2013, 5,940 patients underwent CABG; 212 presented with emergency status. A high proportion of female patients (28.2%) underwent emergency surgery. Emergency CABG patients experienced high rates of intra-aortic balloon pump support, bleeding, dialysis, in-hospital death, and prolonged length of stay. The proportion of emergency coronary artery bypass grafting declined during years 2008-2013 compared with 2003-2007 (2.2% vs. 4.5%, P < 0.001), but the incidence of angiographic accident (5.3% vs. 29.2%) increased as an indication. Ongoing ischemia remains the most frequent indication for emergency CABG, yet the incidence of angiographic accident has greatly increased. In-hospital mortality rates and adverse events remain high. If we look specifically at emergency CABG cases arising from angiographic accident, we find that 14 (15%) of all 93 emergency CABG deaths occurred in that subset of patients. Efforts to improve outcomes should therefore be focused on this high-risk group.

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.

The application of intraoperative transit time flow measurement to accurately assess anastomotic quality in sequential vein grafting

OBJECTIVES

Intraoperative transit time flow measurement (TTFM) is widely used to assess anastomotic quality in coronary artery bypass grafting (CABG). However, in sequential vein grafting, the flow characteristics collected by the conventional TTFM method are usually associated with total graft flow and might not accurately indicate the quality of every distal anastomosis in a sequential graft. The purpose of our study was to examine a new TTFM method that could assess the quality of each distal anastomosis in a sequential graft more reliably than the conventional TTFM approach.

METHODS

Two TTFM methods were tested in 84 patients who underwent sequential saphenous off-pump CABG in Beijing An Zhen Hospital between April and August 2012. In the conventional TTFM method, normal blood flow in the sequential graft was maintained during the measurement, and the flow probe was placed a few centimetres above the anastomosis to be evaluated. In the new method, blood flow in the sequential graft was temporarily reduced during the measurement by placing an atraumatic bulldog clamp at the graft a few centimetres distal to the anastomosis to be evaluated, while the position of the flow probe remained the same as in the conventional method. This new TTFM method was named the flow reduction TTFM. Graft flow parameters measured by both methods were compared.

RESULTS

Compared with the conventional TTFM, the flow reduction TTFM resulted in significantly lower mean graft blood flow (P < 0.05); in contrast, yielded significantly higher pulsatility index (P < 0.05). Diastolic filling was not significantly different between the two methods and was >50% in both cases. Interestingly, the flow reduction TTFM identified two defective middle distal anastomoses that the conventional TTFM failed to detect. Graft flows near the defective distal anastomoses were improved substantially after revision.

CONCLUSIONS

In this study, we found that temporary reduction of graft flow during TTFM seemed to enhance the sensitivity of TTFM to less-than-critical anastomotic defects in a sequential graft and to improve the overall accuracy of the intraoperative assessment of anastomotic quality in sequential vein grafting.

Off-pump coronary artery bypass grafting--the current state

The optimal strategy for coronary revascularization remains controversial. Currently, most surgical revascularizations are performed with the use of cardiopulmonary bypass (ONCAB), yet over the past 20 years off-pump coronary artery bypass grafting (OPCAB) has been increasingly used because of the increased awareness of the deleterious effects of cardiopulmonary bypass (CPB) and aortic manipulation. Small, prospective, randomized controlled trials have lacked sufficient sample size to demonstrate differences in early and long-term outcomes. Larger observational studies that are better powered to statistically compare outcomes have shown more favorable in-hospital outcomes and equivalent long-term outcomes with OPCAB and ONCAB. The benefits of OPCAB techniques may be more apparent for patients at high risk for complications associated with CPB and aortic manipulation. Recent studies have demonstrated improved outcomes in higher-risk patients undergoing OPCAB, as well as improved neurological outcomes. The purpose of this review is to outline the recent literature comparing OPCAB with ONCAB, and to demonstrate efficacy of OPCAB as a useful technique for coronary revascularization.

Clampless off-pump surgery reduces stroke in patients with left main disease

BACKGROUND

Surgical revascularization is the most appropriate therapy for patients with significant left main coronary-artery disease (LMD). An incidence of perioperative stroke remains an issue when compared to the early outcomes to percutaneous coronary intervention (PCI). This study evaluates the safety and impact of standardized "clampless" OPCAB techniques, composed of either complete in situ grafting or "clampless" device enabled techniques for stroke reduction in patients undergoing surgical revascularization for LMD.

METHODS

Between 1999 and 2009, 1031 patients with LMD underwent myocardial-revascularization at our institution. Of these, 507 patients underwent "clampless" OPCAB and 524 patients underwent conventional on-pump CABG (ONCABG). Data-collection was performed prospectively and a propensity-adjusted regression-analysis was applied to balance patient characteristics. LMD was defined as a stenosis >50% and endpoints were mortality, stroke, a cardiac-composite (including death, stroke and myocardial-infarction); a non-cardiac composite and complete-revascularization.

RESULTS

In OPCAB patients, the cardiac composite (3.0% vs. 7.8%; propensity-adjusted (PA)OR=0.27; CI95% 0.12-0.65; p=0.003) as well as the occurrence of stroke (0.4% vs. 2.9%; PAOR=0.04; CI95% 0.003-0.48; p=0.012) were significantly lower while the mortality-rate was well comparable between groups (1.8% vs. 2.5%; PAOR=0.44; CI95% 0.11-1.71; p=0.24). The non-cardiac composite was also significantly decreased after OPCAB (8.9% vs. 19.7%; PAOR=0.55; CI95% 0.34-0.89; p=0.014) and complete revascularization was achieved for similar proportions in both groups (95.1% vs. 93.7%; p=0.35).

CONCLUSIONS

This study shows the superiority of OPCAB for patients with LMD with regards to risk-adjusted outcomes other than mortality. A "clampless OPCAB strategy", effectively reduces stroke yielding similar early outcomes as PCI.

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.

Ostial left main coronary artery stenosis as an additional risk factor in off-pump coronary artery bypass grafting

BACKGROUND

Our aim was to determine whether general left main coronary artery stenosis (LMS) and ostial LMS pose additional risks after off-pump coronary artery bypass grafting (CABG) relative to non-left main coronary artery stenosis.

METHODS

From January 1, 2008, to December 31, 2009, 4366 patients underwent primary isolated off-pump CABG at Beijing Anzhen Hospital. Disease was retrospectively classified as non-left main disease (n = 3523), nonostial LMS (n = 765), and ostial LMS (n = 78). Groups were propensity score matched. Kaplan-Meier freedoms from major adverse cardiac and cerebrovascular events (MACCEs) were calculated.

RESULTS

During the first 30 postoperative days, mortality was significantly higher in the ostial LMS group (6.41%) than in non-left main disease (0.855%, χ(2) = 7.78, P = .005) and nonostial LMS (1.28%, χ(2) = 4.71, P = .03) groups. Incidence of MACCEs was significantly higher in the ostial LMS group (20.5%) than in non-left main disease (5.98%, P = .000) and nonostial LMS (9.62%, P = .002) groups. Odds ratio for early MACCEs of ostial LMS versus non-left main disease was 3.74 (95% confidence interval, 1.72-8.17). At mean follow-up 12.8 ± 7.5 months and cumulative follow-up 498.5 patient-years, difference among groups in freedom from MACCEs did not reach statistical significance (χ(2) = 2.39, P = .303).

CONCLUSIONS

Ostial LMS poses additional early risks of mortality and MACCEs in off-pump CABG. Off-pump CABG for ostial LMS should proceed with greater of intraoperative surveillance and lower threshold for converting to on-pump CABG.