It was a hospital based retrospective study. Duration of the study was the interval between August 1996 and July 2006. One hundred and thirty six TAO patients fulfilling the diagnostic criteria of Olin for TAO who were attending outpatient and inpatient services of Christian Medical College Hospital, Vellore were considered [12]. Case records of patients diagnosed with Buerger’s disease in our hospital were studied; various clinical and laboratory parameters, treatment modalities as well as outcome features were recorded in the defined proforma. As the DEI.Tak form has been available only since 2006, these were filled retrospectively from hospital records for patients who were on routine follow-up until 2006. BVAS scoring was also done for all patients. The study was approved by the institutional research and ethics committee of Christian Medical College Hospital, Vellore.

Patients with signs and symptoms of TAO such as smoking history, age of onset less than 50 years and infrapopliteal arterial occlusion were included in the study. Those who had systemic hypertension, diabetes mellitus, systemic sclerosis, Raynaud’s disease and age of onset greater than 50 years were excluded from the study.

Disease Activity Assessment: Patient details such as demography, disease duration, smoking history, physical findings, routine laboratory tests such as complete blood counts, ESR, liver function tests, renal function tests, fasting blood sugar, lipid profile, routine urine analysis, Chest X-ray PA view and C-reactive protein results were recorded. BVAS and DEI.Tak scoring were done using the medical record data of the patients’ last visits to the hospital. BVAS, a well validated composite scoring system, is used in routine rheumatology practice for monitoring of several systemic vasculitic diseases [10]. As Buerger’s disease is a vasculitic condition, use of BVAS was attempted to assess this disorder. DEI.Tak has been developed as a derivative from BVAS for disease assessment in Takayasu’s arteritis and there is good correlation between the 2 scoring systems in Takayasu’s arteritis [13].

All the patients were classified into two broad subsets based on their clinical outcome. Any patient who underwent any amputation was labeled into the bad outcome group. All the rest who could be managed conservatively by antiplatelet drugs, sympathectomy and revascularization procedures without requiring any amputation were classified within the good outcome subset.

Statistical analysis was done using statistical software SPSS version 13 (SPPS Corp, Chicago, IL, USA). Chi-square and Non parametric Mann-Whitney test were done to correlate outcome with all the parameters recorded including those in BVAS and DEI.Tak scoring.

Between July 1996 and August 2006, one hundred thirty six patients were diagnosed to have Buerger’s disease in our centre. Various demographic parameters are shown in [Table/Fig-1]. All the patients were males. The mean age was 40 years with average disease duration of 4.9 years. All of them were smokers with mean smoking pack years of 14. The mean ankle brachial pressure index on right side was 0.56±0.226 and on the left side, it was 0.62±0.26. All of them had gangrene in either of the lower limbs with loss of pulse. None had gangrene in upper limb.

The patients were further classified into two subset based on their clinical outcome. The comparisons between the groups based on their various clinical parameters and laboratory parameters are shown in [Table/Fig-2]. Claudication pain was seen in 55(46.2%) with in good outcome subset and 64(53.8%) in bad outcome subset. Absent upper limb pulses were seen in 4 (17.4%) and 19 (82.6%), Leucocytosis in 8 (32%) and 17 (68%), Thrombocytosis in 5(31.3%) and 11(68.8%), respectively. The mean BVAS score were 10.29±1.26 and 10.88±2.57 and mean DEI.Tak score were 5.29±1.75 and 7.93±2.43, respectively in the 2 subsets. The absent upper limb pulse and DEI.Tak scores were significantly associated with the bad outcome group.

Present study found smoking as the universal risk factor for the development of lower limb gangrene as well as pulse loss in all patients with Buerger’s disease. This is keeping with the vast majority of publications reporting current or past smoking as prerequisite for the diagnosis of this condition. Non-smokers comprise less than 5% of patients with Buerger’s disease [13]. Cold, frostbite, trauma to the extremities and abuse of sympathomimetic drugs may be the triggering factors amongst the nonsmokers. None of our cases had such a history. Distal lower limb involvement as the disease pattern in Buerger’s disease is a major differentiating point as opposed to involvement of upper limbs in atherosclerotic peripheral vascular disease [8]. However, a significant number of patients with bad outcome amongst our patients had upper limb pulse loss as compared to those who had good outcome. There was no difference in terms of disease duration and pack years of smoking between these two groups in present study.

In this study, the major objective was to assess the patient with Buerger’s disease by the two scoring systems for vasculitic disorders namely BVAS (originally used for ANCA associated vasculitides) and DEI.Tak (usually used to assess disease extent in Takayasu’s arteritis). Both these scores acted well, as tools to evaluate disease outcome in our cohort of Buerger’s disease, as patients with bad outcome and high disease activity had higher scores.

BVAS is like mother of all assessment scores in vasculitic disorders and it is very comprehensive. In this study, DEI.Tak appears to be an ideal disease assessment score for Burger’s disease too, as the later is another pulseless disease with vasculitic etiology similar to Takayasu arteritis. In fact, DEI.Tak is a better tool to assess peripheral pulse loss, which is also an important finding in Buerger’s disease as in Takayasu’s arteritis. Although DEI.Tak scoring system is derived from BVAS, pulse loss is given higher weightage in it [11]. Pulse loss being a major clinical manifestation in Buerger’s disease, therefore, warrants the use of DEI.Tak as disease assessment tool for this illness. Also, we found significantly higher DEI.Tak score in patients with bad outcome as compared to the subset with good outcome. Patients with higher DEI.Tak score had higher risk of amputation due to more severe disease.

Based on present study findings, DEI.Tak can be used as novel instruments to assess and monitor the disease during follow up, as there is no other reliable clinical or laboratory disease activity marker for this disease till date.

As the distribution of vascular lesions in Buerger’s disease is not uniform, it may be important to combine clinical assessment of the patient with the Colour Duplex Ultrasound (CDU) findings, in future studies. However, recent finding of Platelet Microparticle (PMP) levels as a potential biomarker for this disease is encouraging [14,15].

Fazeli B et al., attempted to find a disease-specific activity score for TAO using risk of limb loss associated with each clinical sign or symptom and Complete Blood Count (CBC) data. They noted leucocytosis, anaemia and thrombocytosis in the CBC of TAO patients, in particular those who underwent below knee amputation [16]. However these haematological findings are non specific and can be attributed to many other conditions such as coexisting nutritional anaemia and infections in TAO patients. Hence CBC findings cannot be utilized for scoring of TAO patients in routine clinical practice.

The present study is based on the retrospective analysis of a small scale single center data and hence a multicentric prospective study with larger sample size will be more useful to further validate the current findings.

DEI.Tak scoring can be utilized for assessment of disease activity in patients with TAO in clinical practice. Outcome of this disease can be predicted based on this score.