European Journal of Cardiovascular Medicine

Cardiovascular disease remains the leading global cause of death, with ischaemic heart disease (IHD) contributing the largest share of mortality and disability-adjusted life years across regions and income strata. Despite declines in some high-income regions, absolute burden remains high due to population growth, ageing, and uneven risk-factor control [1]. India bears a disproportionate share, with earlier onset, high case fatality, and accelerating cardiometabolic risk amid an on-going epidemiological transition System-level constraints—geography, pre-hospital delays, referral logistics, and out-of-pocket costs—substantially shape the feasibility of timely emergency cardiac care in the public sector [2,3]. Over the past decade, catheterization capacity and percutaneous coronary intervention (PCI) volumes have expanded rapidly, yet marked heterogeneity in practice persists across regions and care sectors [4].

Large multicentre Indian acute coronary syndrome (ACS) registries have mapped real-world care, documenting reperfusion delays, variability in guideline-directed therapy, and operational constraints [5,6]. International guidance prioritizes primary PCI for ST-elevation myocardial infarction (STEMI) where feasible; when timelines cannot be met reliably, a pharmaco-invasive strategy (early fibrinolysis with planned early angiography/PCI) is endorsed [7,8]. The STEMI-India framework operationalizes this via a hub-and-spoke model with rapid electrocardiography (ECG), door-to-needle fibrinolysis at spokes, protocolized transfer, early angiography/PCI at hubs (within 3–24 h), and continuous monitoring of time metrics with standardized communication and training [9].

Beyond reperfusion, vascular access is a key determinant of procedural safety and efficiency with large randomized trials and contemporary guidelines consistently favouring radial over femoral access for ACS and all-comer PCI owing to lower bleeding and vascular complications without loss of efficacy [10,11]. Lesion preparation is systematic—routine pre-dilatation and high-pressure post-dilatation, complemented when indicated by plaque-modification tools (non-compliant/cutting/scoring balloons, intravascular lithotripsy, selective atherectomy)—and, where feasible, finalized with imaging- or physiology-guided optimization. andomized trials demonstrate that intracoronary physiology (fractional flow reserve, FFR) and intravascular imaging improve lesion selection and stent optimization in appropriate scenarios, translating into improved outcomes compared with angiography-guided PCI alone [12-15]. In India, however, adoption is uneven and generally low due to availability, costs, and workflow constraints. Also, PCI is drug eluting stent (DES)-dominant; drug eluting balloon (DEB) is used selectively—chiefly for in-stent restenosis and small-vessel disease—with proportions varying by public–private setting [2,4].

To address these evidence gaps, we established the prospective Kashmir Cath Registry at a high-volume public tertiary centre in North India to systematically characterise real-world CAG/PCI practice, including case mix, vascular access, STEMI reperfusion pathways, lesion preparation strategies, device portfolios (including DEB), use of intracoronary imaging and physiology, along with procedural safety outcomes.

Study Design and Setting This prospective observational study was conducted at Sher-i-Kashmir Institute of Medical Sciences (SKIMS), Srinagar, a high-volume public tertiary cardiac center in North India. We included all consecutive patients undergoing diagnostic CAG, with or without PCI, during the study period, provided core data elements were available—demographics, cardiovascular risk factors, clinical diagnosis, vascular access, angiographic profile, procedural details, and procedural outcomes. Data Acquisition and Management For all patients, clinical history, 12-lead ECGs, referral documentation, and the working clinical diagnosis were reviewed and archived. Major cardiovascular risk factors (hypertension, diabetes, dyslipidaemia and current smoking) were abstracted from patient history, authenticated prior records, and bedside evaluation. Among STEMI cases, receiving thrombolysis we recorded symptom onset time and symptom-to-needle time to reflect real world total ischemic time. Patients presenting >12 hours after symptom onset without on-going ischemia were classified as late presentation. Vascular access was documented as radial, femoral, or radial-to-femoral crossover. A coronary angiogram was analysed by two interventional cardiologists visually and a vessel having ≥ 50 % diameter stenosis on CAG was considered obstructive and findings categorized as normal/non-obstructive (< 50% stenosis), single-vessel disease (SVD), double-vessel disease (DVD), triple-vessel disease (TVD), or left-main (LM) with other vessel disease. Procedural details captured included use of intracoronary imaging—intravascular ultrasound (IVUS) and optical coherence tomography (OCT)—and coronary physiology assessment with FFR. Lesion preparation and calcium-modification strategies were recorded (cutting/scoring balloons, intravascular lithotripsy [IVL], and rotational/orbital atherectomy), as was stent implantation (vessel and antiproliferative drug) and drug-DEB use. Major procedural complications were prospectively noted, including major bleeding, vascular events, coronary perforation, iatrogenic dissection, stroke, and procedure related death. Statistical Analysis All data were entered into a structured Microsoft Excel worksheet and the analysis was performed on the Excel-derived dataset using standard statistical software. Continuous variables are summarized as mean ± SD (or median [IQR] when non-normal), and categorical variables as counts (%). Ethics This study was approved by the Institutional Ethics Committee of SKIMS, Srinagar.

Patient characteristics, presentation and procedural access:

 Our study cohort of 1850 was predominantly middle-aged (mean age 58.4 ± 11.2 years) with male (80.3%) predominance. Cardiometabolic risk was substantial: hypertension affected 75.7%, diabetes 31.6%, and dyslipidaemia 36.5%. Notably, current smoking was present in 52.4%, underscoring a major modifiable exposure (Table 1). ACS accounted for two-thirds of presentations (66.1%: STEMI 41.1%, NSTEMI 22.4%, UA 2.6%). Within STEMI (n=760), inferior MI was slightly more common (20.4%) than anterior MI (19.0%), while lateral and posterior infarctions were uncommon (1.5% and 0.2%, respectively). Non-ACS presentations were substantial with angina on effort (AOE) comprising 26.0%, and other cardiac conditions (valvular/structural, myocarditis, cardiac dysfunction, arrhythmic and conduction disorders) comprising 7.9% (Table2). Access reflected a radial first approach (72.4%), while femoral route was reserved for complex anatomy or hemodynamic instability (Table3).

STEMI reperfusion strategy:                                           

Overall, STEMI accounted for 41% of all presentations. In Kashmir, mountainous terrain, challenging logistics, and limited cath-lab distribution impede timely primary PCI. Consequently, peripheral thrombolysis has evolved as a cornerstone, often followed by pharmaco-invasive PCI which was the predominant reperfusion pathway (70.4%), whereas primary PCI accounted for 11.2% of STEMI and late presentation accounted for 10.3% of STEMI patients (Table 4).

Table 1. Patient characteristics (n = 1,850).

Table s2. Clinical presentation (n = 1850).

Table 3. Vascular Access.

Table 4. Reperfusion Strategy in STEMI Patients.

Table 5. Coronary Angiographic Profile (N = 1850)

CAG disease profile, interventions, lesion preparation, and vessels treated:

Among 1,850 angiograms, obstructive CAD predominated: SVD 35.7% and DVD 23.8% (combined 59.5%), with TVD 15.2% reflecting a meaningful tail of complex, diffuse disease. Left main with other vessel involvement was present in 2.5%. Notably, normal/non-obstructive angiograms accounted for 22.6% (Table 5). PCI was performed in 1,049/1,850 (56.7%) patients. Within the PCI cohort, stent-only was predominant (79.9%, 838/1,049), with DEB-only in 11.7% (123/1,049) and hybrid (stent plus DEB) in 6.4% (67/1,049); previous old balloon angioplasty (POBA)-only was uncommon (1.3%, 14/1,049). Additional combinations during multivessel PCI included stent plus POBA 0.5%, DEB plus POBA 0.1%; and stent plus DEB alongwith POBA in 0.1%. Overall, 43.3% (801/1,850) had no intervention, reflecting non-obstructive angiography, medical management, or deferred revascularization.

Across 1,190 lesion-level interventions, targets clustered in the LAD (42.9%, 511) and RCA (32.0%, 381), with LCx 20.8% (248); LM and ramus interventions were infrequent (3.2% [38] and 1.0% [12]). Lesion preparation was routine: predilatation 93.1% (977/1,049) and, among stented cases, post-dilatation 92.8% (845/911). In total, 1,087 stents were implanted in 911 patients—predominantly sirolimus-eluting 47.8%, followed by everolimus-eluting 27.0%, zotarolimus-eluting 22.4%, biolimus-eluting 2.3%, and covered (non-DES) 0.4%. Among all patients who actually received a DEB, Paclitaxel-coated balloons were used in about three-fourths (77%), while Sirolimus-coated were used in about one-fourth (23%).

Table 6. Interventions in the Study Cohort (N = 1850)

Adjunctive devices, imaging, and physiology

Among intervened patients (N = 1,049), specialized balloons were used in 10.5%, predominantly cutting balloons 7.8% and scoring balloons 2.6%, with rare combined use  in 0.1%. In 9.0% of intervened patients these devices were deployed as calcium-modification tools; in the remainder, they served predilatation/lesion-preparation roles. Calcium-modification favored balloon-based strategies, with IVL 0.6%, rotational atherectomy 0.2%, and orbital atherectomy 0.1%, indicating limited need for atherectomy.

Intravascular imaging was used in 9.7% of interventions—almost exclusively IVUS 9.4% with minimal OCT 0.3%—suggesting targeted rather than routine imaging for complexity or optimization. In the STEMI-PCI subset (N = 628), thrombus aspiration was uncommon (1.0%), aligned with contemporary evidence discouraging routine aspiration. FFR use was 1.3% (14/1,049), reflecting very limited adoption. Intra-aortic balloon pump (IABP) support was rare (0.6%, 6/1,049).

Table 7. Major procedural complications.

Procedural safety:

Major complications occurred in 48/1,850 (2.6%) patients: death 1.2% (22), major bleeding 0.6% (11), coronary perforation 0.3% (5), vascular complications 0.3% (5), stroke 0.2% (3), and major iatrogenic coronary dissection requiring bail-out stenting 0.1% (2). Major bleeding occurred predominantly with femoral access; two patients developed retroperitoneal haematoma, and the remainder had significant access-site bleeding. Vascular complications comprised iliac artery dissection in two, upper-arm compartment syndrome in two, and a cervical haematoma due to thyrocervical-trunk injury from a 0.035-inch hydrophilic wire in one of the patients.

The cohort was middle-aged (58.4 ± 11.2 years), predominantly male (80.3%), and carried substantial cardiometabolic risk—hypertension 75.7%, diabetes 31.6%, dyslipidaemia 36.5%, and current smoking 52.4%—consistent with NIC/CSI data and related Indian PCI reports that describe younger, male-predominant, high-risk populations [4–6]. Within the ACS subset, 105 patients were ≤40 years (≈8.6%), underscoring the burden of premature ACS [16]. These data mirror national patterns while highlighting especially high tobacco exposure, reinforcing the need for aggressive risk-factor control and protocolized smoking-cessation at discharge.

ACS comprised 66.1% of presentations (STEMI 41.1%, NSTEMI 22.4%, UA 2.6%). This STEMI share aligns with major Indian registries [4–6]. The low UA proportion likely reflects contemporary high-sensitivity troponin use, reclassifying cases historically labelled UA into NSTEMI.

Radial access was achieved in 72.6%, with 5.6% radial-to-femoral crossover. This is concordant with randomized trials and guideline preference for radial-first in ACS/all-comer PCI due to lower bleeding and vascular complications without efficacy trade-offs [10,11], and is consistent with global trends [17]. Crossovers largely reflect anatomic/device constraints or haemodynamic instability; however operator up skilling, standardized bailout protocols, and optimized inventory may further reduce crossover. Given its trainability and cost-efficiency, a radial-first policy remains a pragmatic quality-improvement target for public centres.

STEMI reperfusion—pragmatism within hub-and-spoke geographies:

With STEMI representing ~41% of ACS presentations—paralleling Indian cohorts [4-6]—system workflow favoured a pharmacoinvasive approach, which emerged as the predominant reperfusion pathway (70.4%), while primary and rescue PCI accounted for 11.2% and 8.2%, respectively. These proportions are broadly in line with patterns reported by the NIC/CSI registry for public-sector practice [4]. In contrast, Western registries such as NCDR (United States) and BCIS (United Kingdom) document >70% primary PCI uptake for STEMI, while SWEDEHEART (Sweden) reports >80% [17–19].

The mountainous topography of Kashmir, coupled with challenging referral logistics and an uneven distribution of cath-lab facilities, continues to delay timely primary PCI activation and reperfusion. Consequently, peripheral thrombolysis has evolved as a cornerstone, often followed by pharmaco-invasive PCI within 3-24 hours. A system-level innovation tailored to these constraints is the Save Heart Kashmir (SHK) telemedicine hub-and-spoke model, which employs a secure smartphone-based messaging platform to relay ECGs from peripheral hospitals to tertiary centres, where volunteer specialists respond within minutes to confirm STEMI and activate reperfusion. Its impact has been recognized internationally, with early and subsequent reports highlighting the program’s effectiveness [21,22]. A prior study from Srinagar, conducted before the Save Heart Kashmir (SHK) initiative, documented substantial prehospital delay in STEMI care with only 60.2% of patients undergoing thrombolysis, while 39.8% were ineligible owing to late presentation; the median total treatment delay was 250 minutes, of which prehospital delay contributed 83.8% (median 210 minutes), and the door-to-needle time was 40 minutes. Rural residence and misdiagnosis at first medical contact were key determinants of delay [23]. In contrast, following implementation of the SHK telemedicine-enabled hub-and-spoke pathway at our centre—explicitly targeting these two failure points—operational metrics improved markedly, with symptom-to-needle time falling to a mean of 150 minutes and late presenters contracting to ≈10%. Collectively, these data indicate a system-level shift from predominantly prehospital delays and high thrombolysis ineligibility toward earlier thrombolysis and streamlined pharmaco-invasive transfer, with our high pharmaco-invasive rate reflecting a context-specific, network-driven adaptation.

Figure 1. Impact of Save Heart Kashmir (SHK) in reducing reperfusion times through early tele-ECG and thrombolysis.

Angiographic burden: Our angiographic spectrum—SVD 35.7%, DVD 23.8%, TVD 15.2%, and normal/non-obstructive 22.6%—is broadly congruent with large Indian ACS registries and single centre studies which describe a similar dominance of 1–2 vessel disease.[5,6,16,23]

Intervention mix and optimization: More than half of angiography cases underwent revascularization (56.7%), with a DES-centric program and selective use of DEB and POBA. Our operators used predilatation in 93.1% of all PCI and post-dilatation in 92.8% of stented cases. This strategy complements both DES and DEB strategies, reflecting a prepare-and-optimize philosophy that improves device delivery, expansion, and apposition—key determinants of late outcomes. As our regional STEMI system (Save Heart Kashmir) continues to compress ischemic times, the cath-lab emphasis naturally shifts from simply achieving reperfusion to precision PCI.

Imaging and physiology: Intravascular imaging was used in ~10% of interventions (predominantly IVUS). Randomized data demonstrate that intravascular imaging enhances stent optimization, lowering target-vessel failure and stent thrombosis versus angiography guidance; thus improving long-term outcomes [14,15]. These trials support selectively expanding imaging in anatomically complex segments (long lesions, left main, heavy calcification) to complement our high rates of mechanical optimization. Despite this evidence, real-world penetration remains heterogeneous—often <10% in Western datasets, ≈75–85% in Japan, with Korea/Europe intermediate—reflecting cost, availability, workflow time, and training constraints [24–26]. Indian expert statements likewise note routine imaging in <5% of PCI nationally, citing cost and access constraints—key realities for public centres. Our ~10% use exceeds historical Indian NIC/CSI figures (~4% in 2018) yet remains below evidence-aligned targets [4].

Physiology use was low (FFR 1.3%), in line with national experience. Landmark trials (FAME, FAME-2) show that FFR-guided decision-making improves outcomes versus angiography guidance and that deferral of non-ischaemic lesions is safe [12,13]. Indian data has reached concordant conclusions on clinical effectiveness and efficient resource use in intermediate lesions, arguing for targeted expansion of physiology within our context [27]. Relative to Indian benchmarks, our imaging and FFR adoption is better than historical averages but remains improvable—particularly for complex anatomy and intermediate stenosis where the yield is highest.

Stent and DEB use—patterns and rationale: Revascularization in our cohort was DES-centric: among intervened patients (n=1,049), stenting accounted for 79.9% (n=838), with additional hybrid approach (stent+DEB) in 6.4% (n=67). DEB-only PCI formed a meaningful 11.7% (n=123), and POBA-only was rare (1.3%). This mix reflects contemporary practice in which DES remains the default for most de-novo, large-vessel lesions, while DEB is deliberately deployed in scenarios where a scaffold-free strategy is advantageous—most commonly ISR and de-novo small vessels/side branches after meticulous lesion preparation. The non-trivial DEB share in a public tertiary program suggests operators are selectively prioritizing metal-sparing solutions where recoil risk is low and long-term access (for future PCI or surgery) is a consideration.

Device drug platforms: Across 1,087 stents, our platform mix was broad with sirolimus-eluting 47.8% (n=520), everolimus-eluting 27.0% (n=294), zotarolimus-eluting 22.4% (n=244), biolimus-eluting 2.3% (n=25), and covered stents 0.4% (n=4).This distribution signals two trends: (i) continued, substantial use of everolimus platforms—historically influential in large trials and (ii) a clear shift toward contemporary sirolimus-eluting designs (thin-strut, polymer-optimized, cobalt-chromium/platinum-chromium backbones) that have shown strong deliverability and late safety profiles. For patients receiving a DEB, Paclitaxel-coated balloons were used in about three-fourths (77%), while Sirolimus-coated were used in about one-fourth (23%).

Specialized balloons and calcium modification: We employed specialty/modified balloons in 10.5% of patients—principally for calcium modification in 9.0%, with selective use of IVL 0.6%, rotational atherectomy 0.2%, and orbital atherectomy 0.1%. This pattern reflects a stepwise “prepare-and-optimize” approach endorsed internationally and increasingly adopted in India, reserving atherectomy/IVL for high-burden calcification while relying on cutting/scoring balloons for broader plaque modification. In line with contemporary reviews and Indian series, we frequently paired cutting/scoring balloons or IVL with drug-eluting balloon (DEB) therapy where a scaffold-free strategy was desirable, reinforcing our emphasis on durable lesion preparation followed by tailored anti-restenotic therapy.

Procedural complications: In our study, in-lab complications were infrequent: death 1.2%, major bleeding 0.6%, coronary perforation 0.3%, vascular complications 0.3%, stroke 0.2%, and major iatrogenic dissection 0.1%. These rates compare favourably with contemporary benchmarks. Indian NIC/CSI national data report ~1.5% in-hospital mortality across very large PCI volumes, broadly similar to our 1.2% [4]. Major bleeding in large U.S. Cath PCI analyses has typically been higher (around ~5%), underscoring the contribution of case mix, antithrombotic strategy, and critically radial access to bleeding reduction; our 0.6% aligns with a radial-first approach [28]. Our perforation rate (0.3%) sits within the expected range for contemporary PCI (~0.2–0.4%) and is usually concentrated in heavily calcified or atherectomy cases [29]. Stroke (0.2%) is at the low end of reported PCI series (often ~0.3–0.5%) [30]. Overall, our profile with low bleeding and stroke, rare perforation/dissection—reflects a radial-first, prepare-and-optimize practice with rapid escalation pathways, comparable to best-in-class national and international experience.

Limitations                                                                             

This single-centre, observational registry limits external generalizability and precludes causal inference. As a tertiary referral hub, our case mix may be biased toward higher-risk, complex CAD (selection/referral bias). Outcomes were confined to in-hospital events; we did not capture longitudinal endpoints (e.g., 30-day/1-year MACE), so durability of strategies cannot be assessed. Finally, physiology and imaging penetration was modest (FFR ~1%, IVUS/OCT ~10%), constraining comparative conclusions and quality benchmarking.

In this high-volume public tertiary center in North India, practice is characterized by radial-first access, dominant pharmaco-invasive STEMI management, near-universal lesion preparation, and a contemporary DES portfolio, with notable use of DEB (stand-alone and hybrid strategies) alongside selective deployment of intracoronary imaging, physiology, and calcium-modification devices. The high pharmaco-invasive uptake likely reflects the regional impact of the Save Heart Kashmir (SHK) initiative, which has strengthened early thrombolysis and referral pathways. Collectively, these findings provide a public-sector benchmark and delineate clear opportunities to expand imaging- and physiology-guided PCI.

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