European Journal of Cardiovascular Medicine

Significant renal artery stenosis is one of those underrated clinical disruptors that quietly shapes outcomes in patients who already have enough on their plate especially those presenting for primary percutaneous transluminal coronary angioplasty [1]. Coronary artery disease rarely exists in isolation; it’s basically the billboard announcing widespread atherosclerotic disease throughout the vascular tree. Similarly, the renal arteries are no exception, as when the coronary arteries are severely narrowed and require emergency PTCA, the risk of having renal vascular disease increases significantly [2]. The interrelationship of this pattern is systemic and consistent with the risk profile of the population which disproportionately presents to the cath labs with acute coronary syndromes and has hypertension, diabetes, increased lipids, long-standing smoking, and increased age [3]. The presence of renal artery stenosis is more than an incidental finding on an angiogram for these patients, as the presence of RAS is clinically significant. RAS can worsen the complications and course of the procedure [4]. Resistant hypertension, which is the lack of adequate control with routine antihypertensive management, and more subtle manifestations of renal insufficiency can be seen, as well as more significant hemodynamic changes after the administration of contrast [5]. The renal function of these patients is at risk because they are already functioning at a lower than optimal capacity, and the exposure of these patients with RAS to iodinated contrast significantly increases the risk of contrast induced nephropathy, acute renal failure, a longer length of hospital stays, and higher overall adverse outcome rate [6]. There is a reported unsatisfactory uniformity in the literature regarding the incidence of renal artery stenosis (RAS) in patients undergoing primary PTCA, despite the events being of physiological plausibility. Some literature even reports incidences as low as 5-10% while other literature reports incidences of 30-40% in patients with diffuse atherosclerotic loads. This kind of variability is likely a result of differences in patient selection, the type of gold standard diagnostic test used (whether poor visual estimation angiography vs. duplex vs. CTA/MRA was performed), definitions of the thresholds as “significant stenosis,” and lastly of whether screening of the renal arteries was routinely done or whether the renal arteries were selectively screened [7]. In patients with concomitant peripheral artery disease (PAD) and coronary artery disease (CAD), RAS is more prevalent. Data that was previously recorded via cardiac catheterization with renal angiography (RA) done simultaneously show that RAS is present in 15-20% of patients that also have CAD [8]. RAS is most commonly studied in the context of nonemergency CAD, as recorded in the literature. There is a lack of data regarding the prevalence of RAS in patients with acute myocardial infarction (AMI), even though these patients may present with a unique and poorly understood inflammatory, metabolic, and endothelial profile that may also predispose them to a higher incidence of RAS [9]. The extent of vascular damage in these patients also remains poorly understood, as does multisite atheromatosis and large arteries. There are also very few studies that describe these patients with reduced arterial capacitance [10]. Arterial stiffness increases cardiovascular risk, morbidity, and mortality independent of hypertension, diabetes mellitus, and chronic kidney disease (CKD). A partially understood condition contributing to this risk is renal artery stenosis (RAS). It is frequently underappreciated and shares the same etiological abnormalities as atherosclerotic coronary artery disease (CAD), cerebrovascular disease (CVD), and peripheral artery disease (PAD) [11]. Identifying RAS becomes increasingly significant as it drives the further complication of cardiovascular disease through renovascular hypertension and as it leads to heart failure through the cardiorenal syndrome involving the activating the renin–angiotensin–aldosterone (RAAS) system [12]. In suspected CAD patients undergoing coronary angiography, RAS is a significant prognostic risk factor. It is associated, regardless of confounders and revascularization type, with twice the risk of all-cause mortality. RAS worsens survival with a 21% reduction after 4 years of follow up post catheterization [13]. The mortality increased with the presence of renal insufficiency or PAD. Even asymptomatic individuals with renal artery calcification on CT experienced increased all-cause mortality [14].

Objective

This study aimed to determine the incidence of significant renal artery stenosis in patients undergoing primary PTCA.

This cross-sectional observational study was conducted at, Dept of Cardiology, Adichunchanagari Medical College, Bellur, Karnataka,  India.  A total of 200 patients undergoing primary percutaneous transluminal coronary angioplasty were enrolled to determine the incidence of significant renal artery stenosis in this high-risk population.  Adult patients aged 18 years and above who presented with ST-elevation myocardial infarction or high-risk non-ST elevation myocardial infarction and proceeded directly to primary PTCA were eligible for inclusion. Patients were required to be hemodynamically stable enough to undergo additional imaging of the renal arteries during the same session. Individuals with a known history of renal artery stenosis, prior renal artery intervention, chronic kidney disease stage 5 on dialysis, contrast allergy, cardiogenic shock limiting additional angiography, or incomplete renal artery imaging were excluded from the study.

Data Collection

All patients underwent coronary angiography according to standard institutional protocols. Immediately following coronary intervention, selective angiographic assessment of both renal arteries was performed using a dedicated catheter system. Multiple projections were obtained to enhance visualization and accurately assess luminal narrowing. Significant renal artery stenosis was defined as a luminal reduction of 50% or more, determined by visual estimation. Two independent interventional cardiologists, blinded to clinical profiles and each other’s readings, interpreted the angiograms. Data collected included demographic characteristics (age, gender), cardiovascular risk factors (hypertension, diabetes mellitus, dyslipidemia, smoking), baseline renal function, contrast volume administered, and detailed angiographic findings related to the renal arteries. The primary outcome was the incidence of significant renal artery stenosis among patients undergoing primary PTCA. Secondary outcomes included laterality (unilateral or bilateral involvement), distribution of stenosis severity, and its association with baseline renal function and conventional cardiovascular risk factors.

Statistical Analysis

Data were analyzed using IBM SPSS Statistics version 25. Quantitative variables were summarized as mean ± standard deviation or median with interquartile range depending on distribution. Categorical variables were expressed as frequencies and percentages. The incidence of renal artery stenosis was reported as a proportion of the total sample. Associations between renal artery stenosis and clinical variables were assessed using chi-square test for categorical data and independent t-test or Mann–Whitney U test for continuous variables. A p-value <0.05 was considered statistically significant.

Data were collected from 200 patients, ean age of the cohort was 57.4 ± 10.8 years, indicating a predominantly middle-aged to older population. Males constituted the majority at 142 patients (71 percent), while females accounted for 58 patients (29 percent). Hypertension was the most common comorbidity, present in 136 patients (68 percent), followed by diabetes mellitus in 102 patients (51 percent) and dyslipidemia in 118 patients (59 percent). Almost half of the study population were smokers, with 94 patients (47 percent) reporting active tobacco use. The median baseline serum creatinine was 1.08 mg/dL, with an interquartile range of 0.9 to 1.3 mg/dL, suggesting that most patients entered the procedure with normal to mildly impaired renal function.

Table 1. Baseline Characteristics of Patients Undergoing Primary PTCA (n = 200)

Renal angiographic assessment revealed that 32 out of 200 patients (16%) had significant renal artery stenosis of at least 50%. Among these, unilateral stenosis was found in 24 patients (75%), while bilateral disease was observed in 8 patients (25%). The right renal artery was involved in 18 cases, whereas the left renal artery was affected in 14 cases. Regarding stenosis severity, 20 patients (62.5%) had stenosis between 50–69%, 9 patients (28.1%) had stenosis between 70–89%, and 3 patients (9.4%) had critical narrowing of 90% or greater.

Table 2. Angiographic Findings of Renal Arteries (n = 200)

Comparison between groups showed that patients without significant renal artery stenosis (n = 168) had a mean age of 56.3 ± 10.9 years, while those with stenosis (n = 32) were older, with a mean age of 63.1 ± 9.3 years, a statistically significant difference. Male distribution was similar, with 118 males (70.2%) in the non-stenosis group and 24 males (75%) in the stenosis group. Hypertension was considerably more common in the stenosis group, occurring in 28 patients (87.5%) compared with 108 patients (64.3%) in the non-stenosis group, representing a significant association. Diabetes mellitus was reported in 19 patients (59.3%) with stenosis and 83 patients (49.4%) without stenosis. Dyslipidemia occurred in 21 patients (65.6%) in the stenosis group and 97 patients (57.7%) in the non-stenosis group. Smoking was noted in 17 patients (53.1%) with stenosis compared with 77 patients (45.8%) without stenosis. Median serum creatinine was higher in the stenosis group at 1.24 mg/dL (IQR 1.0–1.4) than in the non-stenosis group at 1.05 mg/dL (IQR 0.9–1.2), showing statistical significance.

Table 3. Comparison between Patients with and Without Significant Renal Artery Stenosis

The present study explored the incidence of significant renal artery stenosis among patients undergoing primary percutaneous transluminal coronary angioplasty and found that 16 percent of the cohort had clinically meaningful renal artery narrowing. This finding reinforces the concept that renal artery stenosis is not a rare incidental pathology in patients presenting with acute coronary syndromes but a relevant and under-recognized comorbidity. Because atherosclerosis is a systemic disease, patients who arrive in the catheterization laboratory with critical coronary lesions often carry parallel involvement of other vascular territories, including the renal arteries. The incidence reported in this study aligns with earlier observations in literature, where prevalence rates generally range between 10 and 30 percent in populations with advanced coronary disease. The association of renal artery stenosis with older age and hypertension in this study is consistent with existing pathophysiological understanding. Patients with established hypertension frequently develop vascular stiffness and endothelial injury, which accelerate atherosclerotic plaque formation within both coronary and renal vasculature [15]. The significantly higher proportion of hypertensive patients in the stenosis group supports the argument that renal artery disease and resistant blood pressure control should be viewed as interconnected clinical entities rather than separate diagnoses. Although diabetes and dyslipidemia were also more common in patients with stenosis, these associations did not reach strong statistical significance, possibly limited by sample size. Still, their higher numerical frequency suggests that metabolic and lipid abnormalities remain important contributors to diffuse vascular disease [16]. The observed increase in baseline serum creatinine among patients with renal artery stenosis further underscores the functional impact of compromised renal perfusion. Reduced renal blood flow not only diminishes glomerular filtration but also restricts the kidney’s adaptive capacity during periods of hemodynamic stress, such as exposure to iodinated contrast during coronary angiography. This raises an important clinical concern: many patients undergoing emergent coronary intervention are already operating with reduced renal reserve, and unrecognized renal artery stenosis amplifies their vulnerability to contrast-induced kidney injury [17]. The predominance of unilateral over bilateral renal artery stenosis in this cohort mirrors the pattern described in previous angiographic and imaging studies. Bilateral disease, though less frequent, carries greater clinical consequence because it affects global renal perfusion and more aggressively impacts blood pressure stability. The eight cases of bilateral stenosis identified here therefore represent a high-risk subset that may benefit from closer follow-up and more tailored blood pressure or renal protection strategies after PCI [18]. Importantly, none of the patients experienced procedural complications from renal angiography, supporting the safety of selective renal artery evaluation when conducted with careful technique and controlled contrast use. These findings carry several clinical implications [19]. First, selective renal artery screening during primary PTCA can uncover vascular disease that would otherwise be missed. Early detection allows clinicians to adjust contrast dosing, optimize hydration strategies, and plan for post-procedural renal monitoring. Second, identifying renal artery stenosis may help explain cases of difficult-to-control hypertension in post-PCI patients and can guide subsequent medical or interventional management. Third, integrating renal vascular assessment into routine angiographic practice especially in populations with high cardiometabolic burden may improve long-term outcomes by supporting a more holistic understanding of the patient’s vascular status. However, this study is not without limitations. Being a single-center observational design, the findings may not fully represent the broader population. The visual estimation of stenosis, although performed independently by two interventional cardiologists, is inherently subjective compared with pressure-based or intravascular imaging modalities. Contrast exposure constraints in acutely ill patients may also limit complete imaging in some cases. Despite these considerations, the study provides meaningful insight into the prevalence and clinical characteristics of renal artery stenosis in patients undergoing primary coronary intervention.

It is concluded that significant renal artery stenosis is a relatively common finding in patients undergoing primary percutaneous transluminal coronary angioplasty, with an incidence of 16 percent in this study population. The strong association with older age, hypertension, and higher baseline serum creatinine suggests that these patients carry a heavier systemic atherosclerotic burden than what is apparent from coronary disease alone. Most cases demonstrated unilateral involvement, although the presence of bilateral stenosis in a notable subset highlights an even higher-risk group requiring closer clinical attention.

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