VELOCITY: Peritoneal hypothermia not associated with reduced infarct size in STEMI

WASHINGTON — Peritoneal hypothermia demonstrated feasibility but failed to reduce infarct size in a cohort of patients with STEMI, concluded findings presented at TCT 2014.

Gregg W. Stone, MD, of Columbia University Medical Center and the Cardiovascular Research Foundation, and colleagues conducted an unblinded randomized trial to evaluate whether systemic hypothermia induced by peritoneal lavage before primary PCI in patients with STEMI was feasible, safe and effective. The study included 28 patients assigned peritoneal hypothermia followed by cardiac catheterization and PCI and 26 controls who were treated with cardiac catheterization and PCI only.

Gregg W. Stone

Hypothermia failed to impact the primary efficacy endpoint of infarct size — defined as percentage of the total left ventricular mass — as assessed by MRI at 3 to 5 days, according to Stone. Rate of total LV mass was 17.2% (15.1-20.6) among patients in the hypothermia group and 16.1% (10-22.2) among controls (P=.54).

“Myocardial salvage was 33% in the hypothermia group and 44% in the control group,” Stone said. “We observed no significant differences in any other measure, including ejection fraction or wall motion score.”

Successful hypothermia was initiated in 96.3% of patients in the study group. Patients in the hypothermia group had a temperature of 34.7°C (34-34.9) at time of the first balloon, whereas those in the control group had a temperature of 36.2°C (35.9-36.7) at this time point (P<.0001)

Both groups demonstrated fast median door-to-balloon times in both arms of the study. These times were 62 (51-81) minutes in the hypothermia group and 47 (37-55) minutes for controls (P=.007).

Angiographic outcomes failed to demonstrate any significant differences between the two groups. Nearly one-quarter of patients undergoing hypothermia reached the composite rate of 30-day safety endpoints (21.4%), whereas 0% of controls reached this endpoint (P=.02). Stone suggested this result was driven by three stent thromboses in the hypothermia arm (10.7%; P=.24).

Other 30-day results indicated a composite MACE rate of 10.7% in the hypothermia arm and 0% for controls (P=.24).

Target vessel and TIMI flow outcomes were similar in the two arms. “The results were pretty typical of what we have come to expect in terms of TIMI flow,” Stone said.

“Controlled systemic hypothermia through automated peritoneal lavage may be rapidly established in patients with evolving STEMI undergoing primary PCI at the expense of a modest increase in door-to-balloon time,” he added.

Cardiac MRI was administered at 3 to 5 days and at 30 ± 7 days. Patients returned at 30 days and 6 months for clinical follow-up.

Stone also described the procedure of inducing hypothermia. Clinicians first lavage the peritoneal cavity with 2.5 L to 4.5 L of lactated Ringer’s solution. Hypothermia is reached at a target temperature of 34.9°C before PCI, after which the cavity is cooled further to reach the target temperature of 32.5°C. This is maintained for 3 hours after the procedure. Clinicians then warm the cavity and drain the fluid.

The study was conducted at seven centers in the United States and Canada. Baseline characteristics were similar between the study groups.

For more information:

Stone G. Plenary Session XIX: Late-Breaking Clinical Trials No. 3. Presented at: TCT 2014; Sept. 13-17, 2014; Washington, D.C.

Disclosure: Stone reports serving as a consultant for Velomedix.