Informed Consent Plays Key Role in Long-Term Outcomes of Cardiac Patients

Patients who required surrogate consent prior to undergoing percutaneous coronary intervention (PCI) had significantly higher all-cause mortality and major adverse cardiac events than those who provided individual consent, according to new findings recently published in the Journal of the American Heart Association.

The study underscores the importance of patient decision-making by highlighting the increased risks that affect those incapable of providing consent, many of whom may require additional support pre- and post-procedure.

“Previous research from the American College of Surgeons Geriatric Surgery Verification Program showed that surrogate decision-making is associated with an increased risk of mortality and serious morbidity among patients who undergo general vascular and orthopedic surgery,” notes Saket Saxena, MD, study coauthor and a geriatrician at Cleveland Clinic. “Because informed consent is a crucial component of any surgery, it is important to understand the additional risks faced by patients who are unable to provide such consent.”

Prompted by prior research and a lack of information on the impact of impaired decision-making on PCI outcomes, Dr. Saxena and his colleagues initiated the first study to compare the long-term outcomes of PCI in patients who provided individual versus surrogate consent.

A closer look at the study

The researchers collected data retrospectively for adults who underwent PCI at Cleveland Clinic’s Heart, Vascular & Thoracic Institute between January 1, 2015, and December 31, 2016. Patients who underwent outpatient PCI as well as those who had major surgery 30 days before or 90 days after PCI were excluded from the study.

The primary outcomes of the study were 2-year all-cause mortality and major adverse cardiovascular events. Secondary outcomes included mean survival, rate of recurrence of acute coronary syndromes, new onset of end-stage renal disease, stroke or cerebrovascular accidents, and length of stay for index hospitalization.

Of the 3,136 patients who underwent inpatient PCI at Cleveland Clinic during the designated period, 183 required surrogate consent. A propensity analysis, which was used to match patients who underwent the procedure with surrogate versus individual consent, yielded 149 patients in each group.

The median age of study subjects was 67 years for both groups, and the majority of patients were male. The underlying reasons for surrogate consent included altered mental status/delirium; severe, active acute coronary syndrome symptoms; intubation or sedation; and a documented diagnosis of dementia.

The researchers reported that 2-year all-cause mortality was significantly higher among patients who provided surrogate consent (38 [25.5%] vs. 16 [10.7%] deaths). The investigation also found that the rate of 2-year major adverse cardiac events was significantly higher in the surrogate consent group—60 events compared to 36 events in those who were capable of providing informed consent.

Implications for the geriatrician

The biggest takeaway from this study, according to Dr. Saxena, is the new understanding that even when undergoing a lower-risk procedure, such as PCI, this group of patients does not perform as well as those who are alert enough to provide informed consent. This has a number of implications, especially for clinicians who manage geriatric patients, whose decision-making may be impaired.

“When caring for older patients with multiple medical problems, many of whom are acutely confused or delirious and may have underlying diagnosed or undiagnosed dementia, it is our responsibility to do everything we can to optimize their outcomes,” Dr. Saxena urges. “We need to not only identify patients at higher risk but also be prepared to closely manage those who cannot provide informed consent.”

This involves a number of potential pre- and postoperative interventions, Dr. Saxena suggests, including preemptively identifying such patients; monitoring their mental status, medications, nutritional status and mobility; closely examining their individual goals; and managing expectations and risks by having in-depth discussions with patients and their families.

“We know that the outcomes for those who cannot provide consent are poor, so the next step is to determine what interventions can help mitigate these risks,” he concludes. “This will require teamwork and additional prospective studies of this vulnerable patient population.”

Remaining research questions

“Our data identify surrogate consent as a risk to be factored into decisions about whether to proceed with PCI, but our findings remain hypothesis-generating,” says the study’s corresponding author, Samir Kapadia, MD, Chair of Cardiovascular Medicine at Cleveland Clinic. “Further investigation is needed to elucidate the causes of the mortality differential we identified and to design strategies to target PCI to appropriate candidates. This will help to improve care and maximize the benefit/risk balance of performing PCI in patients requiring surrogate consent. “