The results of the ISCHEMIA1 trial were presented recently at the American Heart Association’s scientific sessions. This was the largest-ever randomized trial comparing invasive and conservative strategies in patients with stable ischemic heart disease.
The findings indicate that routine percutaneous coronary intervention (PCI) does not reduce major adverse ischemic events relative to the conservative strategy involving optimal medical therapy alone (OMT) in these patients. While the enormous costs of the trial have been criticized, the savings from avoiding unnecessary procedures are potentially far greater.
We hypothesized that … if we randomized the subset that was at greater risk for events – those with moderate-to-severe ischemia – that if there is a benefit to an invasive strategy, we would demonstrate it in this trial.”Dr. Judith Hochman, Cardiologist and Principal Investigator, NYU School of Medicine2
Subset of patients with greatest benefit from invasive strategy
The International Study of Comparative Health Effectiveness With Medical and Invasive Approaches (ISCHEMIA) included 5179 patients with moderate-to-severe ischemia. The degree of ischemia was determined by noninvasive stress testing. This subset of patients is a group considered most likely to benefit from an invasive strategy.
Subjects in the intervention group underwent coronary angiography, followed by PCI or coronary artery bypass grafting as appropriate. Subjects in the control group underwent coronary angiography only if the conservative strategy of medical therapy alone failed. All randomized participants were on OMT and had obstructive coronary heart disease, while none had significant unprotected left main disease. Bias during randomization was avoided by randomizing patients prior to angiography.
Adverse cardiovascular outcomes similar in both groups
The primary endpoint was a composite of five outcomes: cardiovascular death, myocardial infarction, hospitalization for unstable angina, hospitalization for heart failure, or resuscitated cardiac arrest. Over a median follow-up of 3.3 years, this endpoint was observed in 13.3% of the intervention group and in 15.5% of the OMT group (p = 0.34).
These results confirm the findings of the smaller ORBITA2 trial which we reported on previously. In the ORBITA trial, PCI was no better than a sham intervention in terms of increasing exercise time in patients with stable ischemic symptoms.
Should invasive surgery now be discouraged in certain patients, cardiologists will likely need to place extra emphasis on adherence to medical therapy.
So the bottom line is: what do patients care about? They care about living longer and feeling better. … We saw no evidence that they would live longer with a routine invasive strategy and we saw that if they had angina at baseline that would be further improved by an invasive strategy.”Dr. Judith Hochman2
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Author: Sally Hill