TO STUDY WHETHER PRE PROCEDURE HEMODIALYSIS INFLUENCES OUTCOMES AFTER DEOBSTRUCTION PROCEDURE FOR OBSTRUCTIVE UROPATHY

Introduction:

Background/rationale:  Patients with obstructive uropathy often require hemodialysis before deobstructive surgical procedures. A variety of reasons are attributed for this like to prevent decompensated heart failure during and after the procedure, correct electrolyte and acid base imbalances like hyperkalemia and metabolic acidosis, safety in case general anesthesia required, to prevent uremic bleeding and hasten renal recovery and perioperative healing. There is scare data regarding necessity of dialysis before deobstructive procedures and its influence on outcomes and hence this study was undertaken.

Aim and Objective: To study whether pre procedure hemodialysis influences outcomes after deobstruction procedure for obstructive uropathy

Methods:

Materials and methods: Retrospective observational study from Jan 2017 to Sept 2022. All patients admitted under urology/nephrology at tertiary care center undergoing deobstructive procedure and having renal failure {Ser Creatinine > 4 mEq/ dl} were included in the study. Data was sourced using hospital and medical records registers. A comparator arm consisting of patients with serum creatinine > 3 times baseline OR > 4 mEq/dl* Or auric > 12 hrs. undergoing deobstructive procedure and NOT requiring dialysis was utilized.

Primary outcome studied was renal recovery defined as 1. No requirement for dialysis post procedure and /or > 50% increase in 1 month and 3 month eGFR

Secondary outcome: 1. Episode of acute Left ventricular failure 2. Presence of hyperkalemia {Serum potassium > 6 mEq/dl} and metabolic acidosis {serum bicarbonate < 18 mEq/dl}    post procedure 3. Modality of anesthesia: General, Spinal or Local 4. Bleeding per procedurally > 500 ml / Need for PCV transfusion within 1 week of procedure 5. Days of hospitalization post procedure

Sample size: It is a study of independent cases and controls with 1 control(s) per case.  Prior data indicate that the failure rate among controls is 0.78 (75/94).  If the true failure rate for experimental subjects is 0.9 (11/13), a minimum of 145 experimental subjects and 145 control subjects will be required to be able to reject the null hypothesis that the failure rates for experimental and control subjects are equal with probability (power) 0.8.   The Type I error probability associated with this test of this null hypothesis is 0.05.An uncorrected chi-squared statistical analysis will be undertaken  to evaluate this null hypothesis[A1] .

Results:

Results: Total 329 patients were studied out of which 190 did not receive dialysis {non HD group} and 139 required dialysis {HD group} before their deobstructive procedure. Average age was 52.29±14.32 yrs. in Non HD group Vs. 54.83±13.19yrs for HD group. eGFR preprocedure was 29.19±34.85ml/min in non HD group whereas 7.87±8.47 ml/min in HD group. eGFR at 1 month and 3 months’ post deobstructive procedure were not significantly different in both groups (Non HD group 38.02±29 and 32.49±23.96 vs HD group 33.82±28.37 and 34.96±31.08 respectively). Amongst all comorbidities studied, presence of CKD (71.22% in HD group whereas 41.58% in non HD group) and smoking significantly influenced outcome. Uremic symptoms were the most common cause to initiate HD {94.96%}.  Hyperkalemia was the single important indicator for need to dialyze patients {14.74% in non HD group vs 30.72% in HD requiring group}. Interestingly 3 patients of non HD group required dialysis within 1 month of deobstruction whereas 72.66% patient in the HD group did not require dialysis after procedure.  15.82 % patient required ≤3 session dialysis after procedure and  < 5% required > 3 session HD post procedure. Need for HD influenced Anesthesia requirement {Local 47.48% in HD group vs 31.58% in Non HD group, 5.04% spinal in HD group vs 17.37% in non HD group}. There was overall increased perioperative bleeding in non HD requiring group 56.32% vs 43.17% in HD group. 44% having > 500 ml blood loss vs 27.34% in HD group and Hemoglobin drop > 2 gm/dl post procedure 8.95% in non HD group vs. 13.67% in HD requiring group. Renal recovery {eGFR > 50% of preprocedure level} was not significantly different in both groups at 1 month and 3 months’ post procedure. No difference in rehospitalization rates was noted within 1 month of procedure.  All-cause Mortality in 6 months was also not different within 6 months of the procedure with 1 death in non HD group and 3 deaths in HD requiring group.

Among the 36 patient who required dialysis  only after deobstructive procedure  70% had CKD Hb< 10 gm/dl and were oliguric . Dialysis was required due to uremic symptoms in 83.3% . Relative risk of dialysis requirement post procedure is 11.34 times more for patients who required preprocedure dialysis than who did not.

Table (1): Pre procedure required HD Vs baseline parameters

Table (2): Pre procedure required HD Vs Outcome parameters

Conclusions:

Dialysis before deobstructive procedure plays no significant role in renal recovery after the procedure. Presence of chronic kidney disease, Hyperkalemia and uremic symptoms were determinants for need for dialysis before procedure.  There is increased risk of perioperative bleeding in patients who are not dialyzed and undergo deobstructive procedure.  Local anesthesia is preferred for patients who undergo dialysis. Days of hospitalization post procedure were more in dialysis requiring group.rs

I have no potential conflict of interest to disclose.

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