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

Diabetes Mellitus and Lower Extremity Peripheral Artery Disease

Lower extremity peripheral artery disease, or often simply called peripheral artery disease (PAD), is a common cardiovascular disease, as coronary artery disease is. Atherosclerotic disease of the arteries of the lower extremity, or arteriosclerosis obliterans, accounts for the vast majority of PAD today. Rest pain, nonhealing ulcers, and gangrenes associated with chronic ischemia (i.e., Fontaine stage III and IV or Rutherford category 4 to 6) are referred to as chronic limb-threatening ischemia (CLTI), formally called critical limb ischemia (CLI). This narrative review focuses on atherosclerotic PAD, especially CLTI, mainly highlighting its link with diabetes mellitus (DM). This article will first overview the clinical impact of DM in patients with symptomatic PAD and that of symptomatic PAD in patients with DM, followed by the clinical features of CLTI, which will be discussed from a viewpoint of its prognosis, patient profile, onset, and seasonality. DM poses a great clinical impact on CLTI, and vice versa. Patient profile appears different between DM patients complicated with CLTI and the general population with DM. Furthermore, although CLTI is pathologically rooted in atherosclerosis as is acute coronary syndrome (ACS), CLTI has considerably different clinical features compared with ACS. CLTI has an extremely poor prognosis even after revascularization, and there is ample room for improvement in terms of its prognosis. Some measures might be needed in healthcare and clinical settings before revascularization: e.g., DM control and regular ischemia risk evaluation before CLTI onset, proper diagnosis at CLTI onset, and prompt referral to a vascular specialist after CLTI onset, although its evidence is still scanty. Piling up evidence of patients with CLTI, by patients with CLTI, and for patients with CLTI is needed.

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

BACKGROUND

Seasonal variation in coronary artery disease is well described, with a peak in the winter and a trough in the summer. However, little is known about seasonal trends in hospital admission for critical limb-threatening ischemia (CLTI) and associated outcomes.

METHODS

Patients admitted with CLTI from January 1, 2012 through August 31, 2015 were identified in the Healthcare Cost and Utilization Project's National Inpatient Sample based upon administrative claims diagnosis codes. The primary outcome was seasonal hospitalization incidence, and secondary outcomes included mortality rates and rates of in-hospital major and minor amputations among nondiabetics and diabetics.

RESULTS

Of 1,276,745 hospitalizations for CLTI during the study period, 28.3% occurred in the spring, the peak admission season, and 19.1% occurred in the fall, the nadir. In-hospital mortality was highest during the winter (adjusted odds ratio [OR]: 1.08; 95% confidence interval [CI]: 1.03-1.14), and followed the highest seasonal rates of influenza in the fall; however, other important comorbidities did not differ significantly by season. For the overall cohort, there was no significant seasonal variation in rates of major or minor amputation, although seasonal rates were different according to diabetic status. Patients without diabetes had the highest odds of amputation in the spring (OR 1.07; 95% CI: 1.02-1.12), although this trend was not identified among patients with diabetes.

CONCLUSIONS

There is significant seasonal variability in CLTI admissions and mortality but minimal variability in amputation rates. Understanding the seasonal variation in CLTI may help to identify individuals at greatest risk for hospitalization and death through patient and provider education efforts.

Presentation Pattern of Lower Extremity Endovascular Intervention versus Percutaneous Coronary Intervention

AIM

The aim of the current study is to describe the presentation pattern of symptomatic peripheral artery disease undergoing endovascular therapy (EVT) in comparison to symptomatic coronary artery disease undergoing percutaneous coronary intervention (PCI) based on data from nationwide databases.

METHODS

Data were extracted from the nationwide procedural databases of EVT and PCI in Japan (J-EVT and J-PCI) between 2012 and 2017. The presentation pattern was investigated using a Poisson regression model, including the month, seasonality, and weekend (versus weekday) as the explanatory variables. Seasonality was expressed as a cosine function of a 12-month period, and its significance was evaluated using the Fisher-Yates shuffle method.

RESULTS

A total of 41,906 and 62,585 cases underwent EVT for critical limb ischemia (CLI) and intermittent claudication (IC), respectively, whereas 518,858 and 504,139 cases underwent PCI for acute coronary syndrome (ACS) and stable angina (SA). The procedural volume increased by 21.6%, 12.3%, 4.5%, and 3.6% per year in CLI, IC, ACS, and SA. CLI and ACS, but not IC or SA, showed a significant volume seasonality. Compared with ACS, CLI demonstrated a larger peak-to-trough ratio of seasonality (1.75 versus 1.21; P＜0.001), and a later peak appearance (February-March versus January-February by 1.37 months; P＜0.001). The procedural volume on weekends relative to weekdays was smaller for SA, IC, and CLI than for ACS. These distinct features were observed in a diabetic population and a non-diabetic population.

CONCLUSIONS

The current study analyzed nationwide procedural databases and demonstrated the presentation pattern of symptomatic PAD and CAD warranting revascularization.