Abnormal digital brachial index prior to hemodialysis access construction and cardiovascular mortality

Abnormal preoperative digital brachial index is associated with lower 2-year arteriovenous fistula access patency

OBJECTIVE

The aim of the present study was to assess whether a single measurement of the digital brachial index (DBI; systolic finger pressure/systemic pressure ratio), reflecting the arm's circulation, was associated with access patency in patients with severe chronic kidney disease scheduled for arteriovenous fistula (AVF) creation.

METHODS

A bilateral DBI was obtained using digital plethysmography just before construction of the patient's first AVF from January 2009 to December 2017 at one center. A DBI of 80% to 99% was considered normal, and a DBI of <80% (low) or DBI of ≥100% (high) were considered abnormal. DBI values ipsilateral to the AVF were used for analysis. The primary and secondary access patency rates were calculated using reported standards and compared using standard statistical techniques.

RESULTS

Data sets of 163 patients were obtained (69 women; age, 71 ± 12 years). The median follow-up was 40 weeks (range, 0-104 weeks; follow-up index, 99% ± 1%). Patients with abnormal preoperative DBI values had lower 2-year primary patency rates (low DBI, 25% ± 11%; high DBI, 28% ± 6%; normal DBI, 49% ± 8%; P = .018). After correction for age, sex, hypertension, diabetes mellitus, cardiovascular disease, smoking status, and a history of ipsilateral central venous catheter use, an adjusted model demonstrated that abnormal DBI values conferred an increased risk of primary patency failure (low DBI [<80%]: hazard ratio [HR], 2.25; 95% confidence interval [CI], 1.13-4.48; high DBI [≥100%]: HR, 1.74; 95% CI, 1.06-2.85; P < .030 for both). Patients with a low preoperative DBI had also had diminished secondary patency (HR, 2.86; 95% CI, 1.08-7.59; P = .035). In contrast, the diameters of the outflow veins did not determine access patency.

CONCLUSIONS

Patients with abnormal DBI values before AVF construction for hemodialysis had lower 2-year access patency rates compared with patients with a normal DBI. Plethysmographic finger measurements might have a role in the preoperative counseling of patients with severe chronic kidney disease requiring an AVF.

A preoperative modified Allen test result may be associated with long term mortality after hemodialysis access construction

BACKGROUND

The modified Allen test (MAT) is a simple bedside method determining collateral hand circulation prior to hemodialysis (HD) access surgery. Hand ischemia as reflected by low systolic finger pressures (P_dig) is associated with high mortality rates in severe kidney disease (CKD) patients. Aim of the present study was to assess a possible relation between absolute finger pressure drop (∂P_dig) during a preoperative MAT and mortality after a first HD access construction.

METHODS

P_dig (systolic pressure, mmHg) was measured using digital plethysmography following compression of radial and ulnar arteries in CKD patients just before access surgery between January 2009 and December 2018 in one center. The greatest ∂P_dig of both index fingers was used for analysis. Cardiovascular and overall mortality were assessed during the following 4 years using the ERA-EDTA classification system (codes 11, 14-16, 18, 22-26, 29). Cox regression analysis determined possible associations between ∂P_dig and mortality.

RESULTS

Complete data sets were available in 108 patients (male n = 71; age 70 years ±12; mean follow up (FU) 1.6 years ±0.1; FU index 99% ±1). Median ∂P_dig was 31 mmHg (range 0-167 mmHg). Patients having cardiovascular disease (CV+) demonstrated higher ∂P_dig values (CV+ 44 ± 5 mmHg vs CV- 29 ± 3 mmHg, p = 0.012). A total of 26 patients (24%) died during FU (CV+ death, n = 16; 62%). For each 10 mmHg ∂P_dig increase, overall mortality increased by 10%, and CV+ mortality by 15% (overall mortality: HR 1.10 [1.01-1.22], p = 0.048; CV+ mortality: 1.15 [1.03-1.29], p = 0.017). Following correction for age, ∂P_dig remained associated with CV+ mortality (HR 1.13 [1.00-1.26], p = 0.043).

CONCLUSIONS

A large drop in systolic finger pressure during a preoperative MAT is related to mortality after primary HD access surgery. The role of this potential novel risk parameter requires confirmation in a larger population.