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Does angioplasty compare to surgery in the long-term?
Does angioplasty compare to surgery in the long-term?
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PERCUTANEOUS coronary intervention (PCI) for the treatment of multi-vessel disease (MVD) is showing similar outcomes to coronary artery bypass graft (CABG) surgery at five years, reported Professor Friedrich Wilhelm Mohr, Herzzentrum Leipzig/University of Leipzig, Germany, at the recent Transcatheter Cardiovascular Therapeutics (TCT) meeting held in Washington DC, US. In his opening comments, Mohr said that with the development of drug-eluting stents (DES), interventional therapy could improve, however questioned whether the inferior mesenteric artery (IMA) patency would benefit with DES in the long-term, eg. 20 years. Mohr then presented an overview of cardiac surgery in 2002. He explained that 4487 patients underwent surgery, in which 40% had isolated CABG surgery, 20% had PM/ICD, 17% had isolated valve surgery, 9% had combined CABG and valve surgery, 6% had congenital surgery, 4% had aortic surgery and 3% other. There were no transplantations recorded. Interestingly, in 2006, 4581 patients underwent cardiac surgery in which only 25% had isolated CABG surgery, compared to 40% in 2002. Mohr explained that the drop in CABG patients from 40% to 25% is related to a changing surgical population, that is, older patients, increasing comorbidity, worst coronary status ‘post-PCI disease’, and worse left ventricular function. Mohr added that there is increased surgical risk however stable mortality and morbidity. Following this, Mohr described his views on what needs to be done. He said to use bilateral IMA for the left system, which will improve long-term survival and improve freedom from reintervention. He added that avoiding the risk of stroke is also crucial, and to perform all arterial grafting in patients older than 75 years, regardless of diabetes and poor left ventricle function (LVF). Reducing risks and trauma associated with CABG is another challenge that needs to be addressed. Mohr described the ‘Matrix of invasiveness’, explaining that angioplasty and the use of stents has minimal invasiveness however low patency rates compared to CABG and other related surgeries, which have high levels of invasiveness, but higher patency rates. Following this, Mohr reported the angiography six month results from the MIDCAB/BM-STENT randomised trial, comparing coronary artery bypass surgery (n=98) to angioplasty (PTCA) plus stenting (n=106). In the Minimally Invasive Coronary Artery Bypass (MIDCAB) group, 18% showed a stenosis >50% of the anastomoses, and 5% required interventional treatment of a stenosis in the anastomotic region. In the PTCA + stent group, 33% had in stent restenosis >50%, and 27% required repeat PTCA for in stent restenosis. Subgroup analysis showed a restenosis rate of 18% in patients with Type A lesions and up to 56% in Type C lesions. Mohr said that altogether, the rate of reintervention after six months was significantly lower in the MIDCAB group.
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Future developments Some of the possible future developments for treating coronary artery disease could include anastomotic devices, facilitated anastomoses, hybrid revascularisation and computer enhanced TECAB (totally endoscopic coronary artery bypass). Off-pump coronary artery bypass (OPCAB) surgery is also on the horizon, with evidence from over 1500 peer-reviewed papers supporting the procedure. OPCAB reduces risks such as early mortality, neurological complications, renal complications and bleeding, said Mohr. In a series of studies assessing OPCAB versus coronary artery bypass with on-pump surgery, early mortality was investigated (Figure 1). The majority of studies indicated that early mortality was higher in the onpump cohort. In a study by Hannan et al, 2007, intraoperative and postoperative complication rates and adjusted ORs were recorded. Mohr explained that 13,889 patients were assigned to the off-pump surgery group, and 35,941 patients were assign to the onpump surgery group. The incidence of stroke in the off-pump (OPCAB) was 1.2% compared to 1.5% in the on-pump group. Respiratory failure was 3.7% and 4.2% in the off-pump and on-pump groups, respectively. Also, there were differences in repeated revascularisation in the OPCAB versus on-pump groups. It appeared that revascularisation was higher in the onpump group at 93.6% compared to 89.9% in the OPCAB group. Mohr pointed out that improved hospital outcomes appeared to be better in OPCAB patients compared to on-pump patients. Conclusions To conclude, Mohr said that OPCAB has a comparable rate of completeness of revascularisation CABG in stable patients with low mortality rate with both strategies, OPCAB allows for quicker culprit lesion revascularisation, has reduced enzyme release in unstable angina patients only, and reduced morbidity rate in stable haemodynamic situation. OPCAB also has reduced morbidity and mortality in cardiogenic shock, and no effect of operative strategy on long-term follow-up. |
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Interventional versus surgical therapy Next, Mohr discussed the clinical differences between interventional and surgical therapy for the treatment of coronary artery disease. He mentioned the SYNTAX (Synergy Between PCI and TAXUS and Cardiac Surgery) trial. The SYNTAX trial, in which Mohr is the principle investigator, will be one of the first and largest trials to directly compare a DES (the paclitaxel-eluting stent Taxus Express 2, Boston Scientific) with CABG in ‘real world’ patients with complex coronary artery disease (presence of three-vessel disease, left main disease or left main in conjunction with one-, two- or three-vessel disease – left anterior descending, left circumflex. right coronary artery territory). The study is a multi-centre, prospective trial that will involve over 4,200 patients at up to 90 sites in Europe and the US. The trial uses an innovative enrolment methodology that enrols consecutive patients without significant exclusion criteria. Based on an initial assessment, the treating cardiothoracic surgeon and interventional cardiologist will jointly decide whether a patient meets the eligibility requirements for both treatment approaches (CABG and PCI). Patients who are eligible for both treatment options will be enrolled in the randomised arm comparing CABG to PCI, which will include approximately 1,500 patients. Patients determined to be eligible for only one treatment option will be enrolled in one of two ‘nested’ registries tracking either CABG or PCI, which will include approximately 2,750 patients combined. Results from the randomised arm will help compare CABG to PCI in treating patients eligible for both treatment options. The primary endpoint is the 12-month major adverse cardiac and cerebrovascular event (MACCE) rate, which includes death, myocardial infarction, repeat revascularisation and stroke. The nested registries will define profiles of patients eligible for only one of the treatment options. Already actively recruiting, SYNTAX will use an innovative enrolment methodology to recruit patients, using few exclusion criteria. Secondary endpoints include: - MACCE and its components at one and six months, three years and five years
- Characteristics (including co-morbidity and coronary tree scoring) of patients in the randomised arm, the PCI ineligible registry, the CABG ineligible registry, and the ‘preference registry’ (refusal treatment allocation)
- Total cost and cost-effectiveness at one, three and five years
- Quality of Life at 30 days, six months, one, three and five years
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SYNTAX Score Mohr explained that one key objective of SYNTAX is to generate data that will enable physicians to select the optimal revascularisation strategy for high-risk patients. The ‘sYNTAX score’ has been developed with this in mind. This new scoring system incorporates aspects of the modified Leaman score and ACC/AHA lesion characteristics. The SYNTAX score thus prospectively characterises the coronary vasculature in terms of lesion frequency, location, and complexity. Higher scores are indicative of more complex lesions where disease may be expected to have worse short-term outcomes. The lesion and patient complexity data for randomised versus registry cohorts is shown in Figure 2. In reference to the complexity of the disease, Mohr said that, “Patients need to be informed about their individual disease and true options of different revascularisation strategies. Surgeons have to ensure that the proven survival benefit of arterial revascularisation will be offered to all patients by making it the standard of surgical treatment.” Mohr finally implied that new devices for percutaneous coronary intervention will perhaps not make bypass surgery obsolete in the near future.
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