CENTRAL VENOUS STENOSIS, RISK FACTORS, AND OUTCOME IN PATIENTS UNDERGOING MAINTENANCE HEMODIALYSIS: A SINGLE-CENTER EXPERIENCE FROM SOUTH INDIA

Introduction:

Central venous stenosis (CVS) represents a critical complication in patients undergoing maintenance hemodialysis, often resulting in compromised dialysis efficacy and increased morbidity. This study aims to identify the risk factors associated with CVS, evaluate the outcomes of venoplasty procedures, and identify clinical predictors of procedural outcome.

Methods:

This retrospective study was conducted over a two-year period (August 2022 – August 2024) at Government Medical College, Kottayam, Kerala, India. The study cohort comprised 60 consecutive patients who underwent venoplasty for central venous stenosis. Comprehensive data on patient demographics, clinical characteristics, procedural details, and outcomes were collected. Follow-up evaluations were conducted at 1, 3, 6 months, and 1 year post-procedure. Data on patient demographics, clinical characteristics, and procedural details were collected. Critically ill patients were excluded. Follow-up evaluations were performed at 1, 3, 6 months and 1 year post-procedure, and appropriate statistical analyses were conducted to identify clinical predictors of outcomes.

Results:

The study included 60 patients with a mean age of 55 ± 11.89 years (range, 25 to 71 years), with 68.3% being male. Diabetic nephropathy was the most prevalent kidney disease (66.7%), followed by ischemic renal failure (51.7%). The mean age at initiation of renal replacement therapy was 51.48 ± 13.21 years (range, 22-70 years). A history of prior central venous catheterization was present in 93.3% of patients, predominantly in the right internal jugular vein (88.3%). The mean catheter duration was 8.59 ± 6.79 months. Arteriovenous fistula (AVF) was present in 96.7% of patients, with the majority having a brachiocephalic fistula (88.3%). Access failure occurred in 80% of cases, with 51.7% experiencing AVF thrombosis. (Table 1)   

Unilateral central venous stenosis (CVS) was found in 71.7% of patients, and 25% had bilateral CVS. Brachiocephalic vein involvement was the most common (90%). All patients underwent balloon angioplasty, and 23.3% also received stenting. Immediate successful recanalization with symptomatic improvement was observed in 75% of patients. At the 6-month follow-up, 51.3% retained good recanalization, 20.5% had residual stenosis, and 28.2% experienced restenosis. By the 1-year follow-up, only 18.2% had good recanalization, with 81.8% developing restenosis. The mean number of central venous interventions was 1.43 ± 0.83 (range, 1-5). The mean primary patency was 11.43 ± 17.27 months, mean assisted patency was 17.45 ± 18.12 months, and mean patency of new interventions was 0.86 ± 1.91 months. At the end of the study period, 93.3% of patients were alive. (Table 2)

Significant factors associated with immediate poor outcomes included diabetic nephropathy (p = 0.043), right internal jugular tunnelled catheterisation (p = 0.041), and brachiobasilic fistula (p < 0.001). At the 3-month follow-up, smoking (p = 0.026), cerebrovascular accidents (p = 0.005), and diabetic nephropathy (p = 0.019) were associated with restenosis. Left femoral vein non tunnelled catheterisation (p = 0.002) and primary AVF failure (p = 0.008) were more common in the restenosis group, while secondary AVF failure (p = 0.026) was linked to good recanalization. Prominent neck/chest veins (p = 0.006), unilateral stenosis (p = 0.020), bilateral stenosis (p = 0.024), subclavian vein involvement (p = 0.020), and IJV involvement (p = 0.002) were significantly linked to restenosis. Good recanalization was more common with unilateral stenosis (p = 0.020), while restenosis was more frequent with bilateral stenosis (p = 0.024). Subclavian access was significantly associated with restenosis, occurring in 80% of cases (χ² = 8.399, p= 0.020). IJV involvement also showed significant differences (χ² = 12.185, p = 0.002), with 80% of restenosis cases having IJV involvement compared to just 17.5% of good recanalization cases. 

At the 6-month follow-up, smoking showed a moderate association with restenosis (χ² = 6.743, p = 0.036; Cramer's V = 0.42). Left internal jugular tunneled catheterization had a strong association with restenosis (p < 0.001), while left internal jugular non-tunneled catheterization showed a moderate association (χ² = 6.608, p = 0.032; Cramer's V = 0.41). Similarly, left femoral non-tunneled catheter use was strongly associated with restenosis (χ² = 10.296, p = 0.004; Cramer's V = 0.51). AVF failure was moderately associated with restenosis (χ² = 9.809, p = 0.016; Cramer's V = 0.50), with secondary AVF failure showing a stronger link (χ² = 11.775, p = 0.002; Cramer's V = 0.55). Catheter exchange over a guide wire and unilateral stenosis were moderately associated with restenosis (χ² = 7.741, p = 0.029; Cramer's V = 0.45 and χ² = 10.445, p = 0.003; Cramer's V = 0.52, respectively). Subclavian stenosis and stenting had significant associations with restenosis (χ² = 12.370, p < 0.001; Cramer's V = 0.56 and χ² = 8.358, p = 0.013; Cramer's V = 0.46, respectively). 

At the 1-year follow-up, hypertension was strongly associated with restenosis (p = 0.018). Chronic tubulointerstitial disease was associated with good outcomes (p = 0.018). Left internal jugular non-tunneled catheterization, brachiocephalic fistula, history of access failure, AVF failure, secondary AVF failure, and fistuloplasty were significantly associated with restenosis (p = 0.018). The mean number of central venous plasty/interventions was highest in the restenosis group (2.67, p = 0.013). All expired patients had complete occlusion, while 58.9% of survivors had focal stenosis (p = 0.036). Fifty percent of expired patients had inferior venacava involvement, compared to none in the surviving group (p = 0.003). The expired group had a higher number of central venous interventions compared to the surviving group (p = 0.006). 

Conclusions:

Our study underscores key factors influencing venoplasty outcomes in CVS patients on maintenance hemodialysis. Diabetic nephropathy, prior central venous catheterization, proximal AVF, and subclavian vein stenosis were notably linked to poor outcomes. Restenosis remains common, despite an immediate success rate of 75%. Strategies like "Fistula First" and prioritizing distal AVF are vital for better outcomes.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.