Analysis of IN.PACT DEEP trial on the association between changes in perfusion from pre‐ to postrevascularization and clinical outcomes in critical limb ischemia

Abstract

Improvements in toe pressure post revascularization are incremental and rarely normalize. Toe pressure, compared to ankle pressure, is more useful in CLI and predicts future MALE.

Protocol for a prospective observational diagnostic study: intraoperative simultaneous limb pressure monitoring (INSTANT) study

“…Due to the nature of investigating a novel technique, there is limited established evidence to guide expected results for a sample size calculation. The most closely related published data are found in a subgroup analysis of the IN.PACT DEEP trial, which followed patients for 12 months after infrainguinal angioplasty 7. In patients who experienced any improvement of TBI immediately postoperatively, this study identified an HR of 0.15 (95% CI 0.04 to 0.57) of ‘MALE’ within 1 year, defined as major limb amputation above the level of the ankle, or major target lesion revascularisation in the form of thrombolysis, thrombectomy or bypass.…”

“…The primary outcome of this study will be defined as MALE. The expected 1-year event rate of MALE is higher in subjects with critical limb ischaemia (20.5%7 vs subjects with claudication 3.2%) 20. Based on a recent 10-year audit of endovascular procedures performed at the investigational centre (The Ottawa Hospital, Civic Campus) the expected proportion of eligible subjects with critical limb ischaemia (vs claudication) is 0.625.…”

“…The change in ABI following endovascular surgery can be detected a day after the procedure, and remains stable throughout the month following the procedure 6. While the ABI is commonly used for monitoring haemodynamic improvement after endovascular surgery, postoperative surveillance TBI has been demonstrated to have a significantly stronger correlation with clinical outcomes such as major adverse limb events (MALE) 7. ‘MALE’ is defined as a composite outcome of clinically driven target limb reintervention and major amputation 8.…”

Infrapopliteal peripheral arterial disease and critical limb ischemia: The time has come for collaborative, streamlined diagnostic, and treatment paradigms

“…Although the current study by Hammad et al is small and underpowered, it should be seen as a call to arms for the societies who have a stake in vascular disease. It is time to come together on these important issues.…”

“…In this issue of CCI , Hammad et al report a study in which they took a closer look at the IN.PACT Deep data and focused on methods of surveillance used in patients who underwent below knee endovascular revascularization for critical limb ischemia. In particular, they looked at the utility of ankle‐brachial index (ABI), ankle pressures, toe‐brachial index, and toe pressures in these groups.…”