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For patients undergoing percutaneous coronary intervention (PCI), procedural complications are only responsible for a small fraction of the already low number of deaths that occur, according to a study published online February 28, 2012, ahead of print in Circulation: Cardiovascular Quality and Outcomes. The authors say that further reductions in PCI mortality will require efforts outside of the cath lab.
Hitinder S. Gurm, MD, of the University of Michigan Cardiovascular Center (Ann Arbor, MI), and colleagues evaluated data from 5,520 patients undergoing PCI from 2001 to 2009 at their institution. Two interventional cardiologists and 1 noninvasive cardiologist reviewed 85 cases that resulted in mortality (1.54%) to determine the cause and circumstance.
Procedural Complications Not at Fault
Left ventricular failure was the most common cause of death (35.3%), followed by neurological complications (16.5%) and arrhythmia (12.1%). At least 2 reviewers agreed on cause of death in 87.1% of cases. All 3 reviewers agreed on 47.1% of cases. In instances when the interventional cardiologists agreed (61.2%), the general cardiologist disagreed with the consensus only 21.2% of the time.
The circumstance of death was mostly acute cardiac (52.9%) followed by noncardiac (12.9%) and procedural complication (7.1%). At least 2 reviewers agreed on circumstance of death in 85.9% of cases (n = 73). All 3 reviewers agreed on the circumstance in 54.1% of cases. In instances when interventional cardiologists agreed (70.5%), the general cardiologist disagreed with the consensus only 23.3% of the time.
Importantly, most deaths (93%) were attributed to preexisting or post procedural disease processes and therefore considered unpreventable.
Issues Start Before PCI
In a telephone interview with TCTMD, Dr. Gurm said that most deaths occurred because of irreversible conditions present prior to PCI.
“We see patients come in with cardiogenic shock. They get PCI, but they cannot survive that,” he said. “Other patients come in with neurological injury. They have out-of-hospital arrest. We take them to the cath lab, and then they survive their heart attack but die from their stroke.”
Dr. Gurm suggested that PCI-related mortality could further be reduced by actions taken either in the ambulance or emergency room before PCI. For example, hypothermia or other therapies could be employed to reduce the effect of shock before the patient enters the cath lab.
Regardless, he was surprised to find that the interventionalists were more likely to classify deaths as preventable compared with the noninvasive cardiologist. In the study, the noninvasive cardiologist did not classify any of the deaths as “strongly” or “mostly” preventable. “As interventionalists, we tend to be harsher on ourselves,” Dr. Gurm supposed.
Quality Metrics Questioned
In light of previous studies, David J. Cohen, MD, of the Saint Luke's Mid America Heart Institute (Kansas City, MO), said the current results are “striking.”
“We’ve always known that to a large degree, deaths after PCI are predictable,” he commented to TCTMD in a telephone interview. “[The fact that prediction models work as well as they do] tells you is that the fate of the patient is determined before they actually have their cath lab procedure. It’s dependent on their comorbidities and their level of acuity in those other factors, and what we do in the cath lab has only a very modest ability to change that both for the good and the bad to some degree.”
Ajay J. Kirtane, MD, SM, of Columbia University Medical Center (New York, NY), told TCTMD in a telephone interview that assuming deaths after PCI arise from the procedure can be problematic, because mortality data are being increasingly used as a quality-of-care metric.
“There are hospitals that will advertise on that basis, there’s talk of insurance companies reimbursing on that basis, and certain patients when these data are made public will likely make treatment decisions on that basis,” he said.
Dr. Gurm agreed. “There’s all this pressure that we should be reporting all deaths publicly,” he said. “Normally you would want to report outcomes where you could do something different to help improve them. In my observation, the patients that were dying were the ones who came in so sick. They did not die because of what we did—they died despite what we did.”
Since New York State started reporting all PCI-related deaths, there has been a reduction in the number of patients with shock who, once admitted to the hospital, were sent to the cath lab, Dr. Gurm observed. “That means that there may have been patients who might have lived because they were not taken to the lab,” he said. “There’s concern [among hospitals that their] mortality numbers would look bad. Institutions involved in public reporting need to pay attention to how many of these deaths were preventable vs. unpreventable.”
Looking at the Broader Picture
Going forward, Dr. Cohen said the current system of penalizing sites that treat “high risk, high reward cases” needs to be reevaluated. “Taking on high risk cases where the benefits are small does not make any sense, but many of the highest risk cases are where we can really save the most lives and provide the most benefit,” he stressed.
Dr. Cohen would like to see if these findings can be replicated across a larger geographic area or the whole country. That way, “if it turns out that there are certain centers that have a smaller or larger proportion of preventable deaths, then we need to understand what the better hospitals are doing and what the worse hospitals are doing,” he said.
Within the next year, the Michigan researchers will look at all PCI-related deaths in the state, Dr. Gurm noted, adding that the effort will allow comparisons across multiple institutions and suggest ways to reduce mortality.
The take home message, Dr. Kirtane concluded, is that “we need to do a better job of figuring out what metrics translate most directly from PCI-related complications. We need to stop emphasizing post-PCI mortality as the default metric for evaluating performance.”
The mean time from PCI to death was 7.13 ± 8.14 days. Patients died more frequently when presenting in cardiogenic shock, after cardiac arrest, or ventricular arrhythmias. Survivors tended to be younger and have lower rates of congestive heart failure, better left ventricular ejection fraction, less atrial fibrillation and noncardiac vascular disease, and higher rates of prehospital ACE inhibitor and beta-blocker use compared with nonsurvivors.
Most deaths (82%) occurred in patients undergoing emergent or urgent PCI. Of the patients who died, 56% were undergoing PCI for STEMI, while 36.4% had presented with cardiac arrest, ventricular tachycardia, or atrial fibrillation and 44% had presented in cardiogenic shock.
Valle JA, Smith DE, Booher AM, et al. Cause and circumstance of in-hospital mortality among patients undergoing contemporary percutaneous coronary intervention. Circ Cardiovasc Qual Outcomes. 2012;Epub ahead of print.