Prediction of imminent amputation in patients with non-reconstructible legischemia by means of microcirculatory investigations

Purpose: We investigated the usefulness of skin microcirculatory investigat ions to predict imminent major amputation in patients with non-reconstructi ble critical limb ischemia. Methods: One hundred eleven patients with non-reconstructible chronic rest pain or small ulcers and an ankle blood pressure of 50 mm Hg Or less or an ankle-to-brachial pressure index of 0.35 or less were included. Nailfold ca pillary microscopy (Chl; big toe, sitting), transcutaneous oxygen pressure (TcpO(2); forefoot, supine; 44 degrees C), and laser Doppler perfusion meas urements (LD; pulp of big toe, supine) were performed at rest and during re active hyperemia. Patients were classified according to their skill microci rculatory status just before the start of the treatment in three groups: th ese with a "good," "intermediate," or "poor" microcirculation, according to a combination of predefined cutoff values (Poor: capillary density less th an 20/mm(2), absent reactive hyperemia in CRI and LD, TcpO(2) less than 10 mm Hg; good: capillary density of 20/mm(2) or more, present reactive hypere mia in CRI and LD, TcpO(2) of 30 mm Hg or more). Subsequently, patients rec eived maximum conservative therapy from the surgeon, who was unaware of the microcirculatory results. After a follow-up period of as long as 36 months , limb survival and disposing factors were analyzed and compared with the i nitial microcirculatory status. Results: Cox regression analysis showed a significant prognostic value of t he microcirculatory classification (hazard ratio = 0.28, P <.0001), but not of the Fontaine stage, ankle blood pressure, or the presence of diabetes m ellitus for the occurrence of an amputation. Positive and negative predicti ve values were 73% and 67%, respectively. The cumulative limb survival at 6 and 12 months was 42% and 17% in the poor microcirculatory group, 80% and 63% in the intermediate microcirculatory group, and 88% and 88% in the good microcirculatory group (P <.0001, log-rank). Conclusion: Microcirculatory screening and classification is useful in dete cting non-reconstructible critical ischemia that requires amputation, which is not detectable by means of the clinical stage or blood pressure paramet ers. Most of the poor patient group will require amputation. In the interme diate and good groups, nonsurgical treatment appears sufficient for limb sa lvage.