Seasonal Variation in Critical Limb Ischemia Requiring Endovascular Therapy: An Analysis of a Multicenter Database of Japanese Patients with Critical Limb Ischemia Undergoing Endovascular Therapy

Abstract

Aim:We investigated whether any seasonal variation is observed in the incidence, severity and prognosis of critical limb ischemia (CLI) requiring endovascular therapy. Methods: We analyzed a multicenter database of 1,568 consecutive CLI cases undergoing primary endovascular therapy for infrainguinal lesions between July 2004 and June 2011. The monthly incidence was assessed according to the cumulative number of cases in each month, using a simple moving average. The data were fitted to a nonlinear regression model with a cosine function. The monthly proportion of cases in each Rutherford classification among the overall CLI population was assessed using a multinomial logistic regression model. The monthly risk of major amputation was evaluated using a Cox proportional hazard regression model. Results: Significant seasonal variation was observed in the incidence of CLI ( p＜0.01). It was higher in the period from winter to spring, with a peak in March, and lower in the period from summer to autumn, with a trough in September; the fold difference between the peak and trough was 2.2. The seasonal variation was more markedly observed in the cases with a more severe Rutherford class. The proportion of cases in each Rutherford class among the overall CLI population also exhibited significant seasonal variation ( p＜0.01). In addition, the risk of major amputation demonstrated significant seasonal variation ( p=0.03); however, the statistical significance was lost following adjustment for the Rutherford classification ( p = 0.10). Conclusions: Seasonal variation is observed in the incidence and severity of CLI. The seasonality of the limb prognosis is likely explained by that of the CLI severity.

Seasonal variation in U.S. hospitalizations for chronic limb‐threatening ischemia

“…Since PAD shares overlapping risk factors and pathophysiology with CAD, we hypothesized that CLTI would show significant seasonal variation. Supporting this hypothesis, a small Japanese registry reported a peak incidence and treatment of CLTI during the winter months 17 and seasonal variations in amputations were observed in a New York State cohort 18 . Characterization of seasonal variation in CLTI hospitalization and outcomes may allow for targeted identification and treatment of vulnerable patients as well as to help identify modifiable environmental risk factors.…”

Diabetes Mellitus and Lower Extremity Peripheral Artery Disease

“…As does ACS (42) , CLTI has seasonal variations in incidence, severity, and prognosis. Our former study analyzing 1568 patients with CLTI undergoing EVT demonstrated that the number of patients were smallest from summer to autumn and largest from winter to spring (43) . The severity (assessed with the Rutherford classification) and risk for major amputation also presented significant seasonal variation, with the peak roughly in winter and the trough roughly in summer.…”

Presentation Pattern of Lower Extremity Endovascular Intervention versus Percutaneous Coronary Intervention

“…However, data were so far limited regarding lower extremity peripheral artery disease (PAD), another cardiovascular disease that has now become a global health problem 4 ) and attracted increasing clinical attention 5 – 8 ) . We previously reported the seasonal variation of critical limb ischemia (CLI) undergoing endovascular therapy (EVT) 9 ) , but it remained to be validated by nationwide databases. Furthermore, whether another major symptomatic manifestation of PAD, namely, intermittent claudication (IC), will also have seasonal variation is still unrevealed.…”