**2. Stable coronary artery disease**

The correlation of BMI with clinical endpoints in the setting of interventional coronary revascularization from a single‐center experience in patients (*n* = 3571) receiving balloon angioplasty was first reported in 1996 [14]. A detailed study of the in‐hospital outcomes suggested higher rates of mortality (2.8% vs. 0.9% vs. 3.7%; *p* < 0.001) in normal weight and obese patients as compared to overweight patients. This bias could also noted in the patients' need for blood transfusions (11.9% vs. 7.4% vs. 8.4%; *p* = 0.003) and their corresponding rise in creatinine value >1 mg/dl (3.6% vs. 1.8% vs. 1.8%; *p* = 0.018). Interestingly, the rates of myocardial infarction did not reflect any such patient group preference (3.5% vs. 3.4% vs. 4.7%; *p* = n.s.). The multicenter BARI registry evaluated the BMI of 3634 patients undergoing elective revascularization [2108 by interventional procedure (PCI) and 1526 by surgery (CABG)] at study entry between 1988 and 1991 [15]. Initial analyses of the results elicited a correlation between the body mass index and an increased risk of a major in‐hospital event in the PCI arm. At the five‐year follow‐up interval, this correlation between BMI and mortality existed only in the CABG arm. The final results from the BARI registry suggested an inverse relationship between BMI and in‐hospital outcome post‐PCI without any major difference in long‐term follow‐up. Interestingly, although the study by Gruberg et al. [11] did indicate an inverse relationship in the 9633 patients evaluated between 1994 and 1999 at the 12‐month follow‐up for mortality (10.6% vs. 5.7% vs 4.9%: *p* < 0.0001), rates of myocardial infarction (7.4% vs. 7.0% vs. 6.7%: *p* = 0.66) and target vessel revascularization (20.2% vs. 22.0% vs. 22.4%: *p* = 0.16) did not vary significantly. Certain post‐procedural clinical events like arterial hypertension, pulmonary congestion, impairment of renal function, bleeding events, access site complications, as well as those leading to mortality were seen more often in underweight patients as compared to the overweight and obese patient cohort.

 mortality [3, 4]. It is for this reason that initiatives detailing the primary and secondary prevention of cardiovascular disease in overweight and obese patients have laid specific emphasis on the significance of weight loss so as to modify cardiovascular risk [5–7]. Obese patients have an increased preponderance to develop atherosclerotic disease, especially coronary artery disease, which is characterized by a reduced sensitivity to insulin, enhanced free fatty acid turnover, increased basal sympathetic tone, a hyper‐coagulable state, and finally with promotion of systemic inflammation [8, 9]. Population‐based data suggest that 43 and 24% of all coronary revascularization in recent years were carried out in overweight and obese patients, respectively [10]. It has been speculated that the obese patient cohort is somehow associated with a clinical outcome far worse than that of a normal weight patient, and this theory is further substantiated by the existence of evidence describing the causative association of morbid obesity in cardiovascular disease. Interestingly, contemporary studies have recently elucidated the role of an "obesity paradoxon," describing the protective effect of obesity (when considering postoperative morbidity and mortality) in patients receiving either surgical or minimally invasive coronary revascularization [11]. This observation suggesting a better clinical outcome for obese patients is not only restricted to the clinical setting of coronary revascularization, as similar data have also been reported in cases of an acute myocardial

In this review article, we attempt to present an overview and summarize the evidence docu-

The correlation of BMI with clinical endpoints in the setting of interventional coronary revascularization from a single‐center experience in patients (*n* = 3571) receiving balloon angioplasty was first reported in 1996 [14]. A detailed study of the in‐hospital outcomes suggested higher rates of mortality (2.8% vs. 0.9% vs. 3.7%; *p* < 0.001) in normal weight and obese patients as compared to overweight patients. This bias could also noted in the patients' need for blood transfusions (11.9% vs. 7.4% vs. 8.4%; *p* = 0.003) and their corresponding rise in creatinine value >1 mg/dl (3.6% vs. 1.8% vs. 1.8%; *p* = 0.018). Interestingly, the rates of myocardial infarction did not reflect any such patient group preference (3.5% vs. 3.4% vs. 4.7%; *p* = n.s.). The multicenter BARI registry evaluated the BMI of 3634 patients undergoing elective revascularization [2108 by interventional procedure (PCI) and 1526 by surgery (CABG)] at study entry between 1988 and 1991 [15]. Initial analyses of the results elicited a correlation between the body mass index and an increased risk of a major in‐hospital event in the PCI arm. At the five‐year follow‐up interval, this correlation between BMI and mortality existed only in the CABG arm. The final results from the BARI registry suggested an inverse relationship between BMI and in‐hospital outcome post‐PCI without any major difference in long‐term follow‐up. Interestingly, although the study by Gruberg et al. [11] did indicate an inverse relationship in the 9633 patients evaluated between 1994 and 1999 at the 12‐month follow‐up for mortality (10.6% vs. 5.7% vs 4.9%:

infarction and heart failure [12, 13].

182 Adiposity - Omics and Molecular Understanding

**2. Stable coronary artery disease**

mented on "obesity paradoxon" in coronary artery disease.

The Scottish Coronary Revascularization Register offers another perspective to this debate. In contrast to previous all‐comers trials, this study included only those patients (*n* = 4880) undergoing elective PCI between 1997 and 2006, and without any known history of coronary artery disease. Patients evaluated to have a BMI in the range between 27 and 30 kg/m2 were linked with lower all‐cause mortality after 5 years of follow‐up as compared to other weight groups. The introduction of a blanking time (<30 days) to exclude periprocedural events as well as an adjustment to different baseline data did not impact the outcome of their study [16]. These conclusions were reaffirmed in the APPROACH registry, where a collective of 310,121 patients were treated conservatively (*n* = 7801), by PCI (*n* = 7017), or by CABG (*n* = 15,601) [17]. Lower mortality rates were recorded among overweight and obese patients as compared to normal weight patients in the cohort treated conservatively. These findings were also consistent for the CABG as well as the PCI group. An interesting corollary to these results centered around the use of bare‐ metal stents (BMS) as well as a discussion on the meta‐analysis of these single trials, suggesting an inverse relationship between BMI and the clinical outcome after stenting [18]. The results from studies of the balloon angioplasty and the BMS era are in stark contrast to other studies conducted in this timeframe, wherein patients receiving any of the two stents, DES or BMS, did not observe the "obesity paradoxon." An additional note in this context is summarized by the study of Poston et al. conducted in 1631 patients, suggesting that normal weight patients were older than obese or overweight patients at the time of hospital admission [18]. The 1‐year follow‐up mortality and risk for procedure revision were comparable in both groups.

In the TAXUS trials, of the 1307 patients stratified according to BMI and type of stent used (BMS versus DES) [20], higher rates of BMS in‐stent restenoses were observed in obese and overweight patients than in normal‐weight patients (29.2% vs. 30.5% vs. 9.3%; *p* = 0.01). The patients receiving DES had major cardiac event (MACE) rates skewing in favor of normal weight patients, and however, the clinical event rates in these different patient groups did not vary significantly. Subsequent results obtained from the German DES.DE registry would also validate these findings [21]. A total of 5806 patients assimilated from 98 sites in Germany were included in this registry for DES patients and followed up over a period of 12 months. The results would summarize suggestions made in previous trials, stating that the baseline comorbidity index was higher in obese patients as compared to overweight and normal weight patients, while the rates of in‐hospital events were similar in all three groups. The follow‐up after 1 year indicated no significant variability in mortality rates (3.3% vs. 2.4% vs. 2.4%; *p* = 0.17), myocardial infarction (2.8% vs. 2.3% vs. 2.3%; *p* = 0.45), target vessel revascularization (10.9% vs. 11.7% vs. 11.6%; *p* = 0.56), and major bleeding


**Table 1.** Overview of literature addressing the "obesity paradox" in patients suffering from stable coronary artery disease undergoing coronary angiography and/or revascularization.

(2.5% vs. 2.1% vs. 2.8%; *p* = 0.53) between normal weight, overweight, and obese patients, respectively (**Table 1**).
