Temporal trends reveal increasing mortality rates for patients undergoing percutaneous coronary intervention (PCI) for the complex case of acute myocardial infarction (MI) coupled with cardiogenic shock, a registry study found.

In-hospital death for patients, who were managed with an early invasive strategy, climbed from 27.6% in 2005-2006 to 30.6% in 2011-2013 (OR 1.09, 95% CI 1.005-1.173), according to Siddharth Wayangankar, MD, MPH, of Cleveland Clinic, and colleagues in JACC: Cardiovascular Interventions.

Even the "evolution of medical technology and utilization of contemporary therapeutic measures" have failed to curb the trend, the authors noted.

In an accompanying editorial, Tanveer Rab, MD, of Emory University Hospital in Atlanta, called the increasing mortality "disturbing," adding that "we must carry on and hope that mortality trends can be reversed."

Wayangankar's study included 56,497 patients from the Cath-PCI Registry -- maintained by the National Cardiovascular Database Registry -- who entered the cath lab between 2005 and 2013.

Between 2005-2006 and 2011-2013, the use of intra-aortic balloon pumps fell (49.5% versus 44.9%, P<0.01), as did the popularity of drug-eluting stents (65% versus 46%, P<0.01).

Survival was associated with female sex (OR 0.94, 95% CI 0.89-0.97), prior PCI (OR 0.78, 95% CI 0.74-0.82), and a BMI of less than 30 kg/mm2 (OR 0.98, 95% CI 0.97-0.98).



Bleeding events within 3 days of PCI declined (11.5% in 2005-2006 versus 8.7% in 2011-2013, P<0.01) as bivalirudin became more common over the years (12.6% versus 45.6%, P<0.001).

Additionally, there was a falling proportion of ST-segment elevation myocardial infarction patients (STEMI) who make it to the hospital within 6 hours of symptom onset (88.1% versus 77.2%, P<0.001).

"This is despite the recent advances in medical technology, aggressive education efforts (e.g., "time is muscle"), and revamping of several health care strategies to ensure prompt care for acute MI patients," Wayangankar and colleagues noted. This is bad news for those with cardiogenic shock, "who are inherently at a higher risk for poor outcomes; particularly if therapeutic intervention is delayed."

The authors found that the most common reason for delay in PCI was cardiac arrest or need for intubation, which accounts for 70% of setbacks. "The latter problem may be better dealt with by streamlining the rapid response teams and educating the catheterization laboratory personnel to work synergistically with other ancillary staff so that multi-tasking can be achieved without significant delay," they suggested.

Even so, "without adequate clopidogrel treatment or absorption, ischemic events and mortality increased with bivalirudin use," Rab speculated, who recommended clinicians use glycoprotein IIb/IIIa inhibitors "since clopidogrel absorption is an issue."

The authors cited the voluntary nature of the CathPCI registry as one of the study's limitations, along with the lack of data on longer-term outcomes. There were also "only a small number of hospitals that consistently submitted patients during the entire study time frame," so a revolving door of institutional participants may have introduced the effects of hospital differences.

Nonetheless, there seem to be clear areas of improvement for clinicians in the cath lab.

"What is surprising is the low utility of mechanical circulatory support devices (7.2% in 2011-2013), such as Impella, Tandem Heart, or extracorporeal membrane oxygenator, even in high volume centers," Rab wrote. "These devices benefit patients in cardiogenic shock by improving cardiac power output, if placed early, prior to PCI."

According to Rab, clinicians should opt for early mechanical circulatory support, as American and European guidelines on myocardial revascularization already "provide a class IIb recommendation for short-term mechanical circulatory support in acute coronary syndrome patients with cardiogenic shock."

Other steps that can be taken to lower the incidence of mortality, he continued, include "using heparin as an anticoagulant instead of bivalirudin;" "aiming for complete revascularization;" "using second-generation drug-eluting stents;" and "switching to radial access for PCI."