Approximation of the Ankle-Brachial Index in the Setting of Medial Arterial Calcific Sclerosis.

The presence of medial arterial calcific sclerosis is known to cause inaccuracy in the interpretation of noninvasive vascular testing. This substantially limits the utility of an important baseline diagnostic test for peripheral arterial disease. Therefore, the objective of this investigation was to derive a method to effectively factor out calcification in the interpretation of the ankle and digital brachial indices. The noninvasive vascular testing results of 160 subjects were stratified into the absence of calcification, mild calcification, moderate calcification, and severe calcification based on plain film radiographic findings of the infrageniculate vessels. Measurements were then performed of the pulse volume recording (PVR) waveforms at brachial, ankle and digital anatomic levels to include PVR wavelength and PVR upstroke length, with a calculation of the ratio of PVR upstroke length to PVR wavelength. These measurements were compared between groups and then correlated to the ankle and digital brachial indices. A significant difference was observed in the PVR upstroke ratio between the 3 anatomic levels (0.1818 vs 0.2622 vs 0.3191; p < .001), but not between the 4 calcification groups (0.2457 vs 0.2363 vs 0.2694 vs 0.2631; p = .242). A significant negative correlation was observed between the PVR upstroke ratio and the ankle brachial index (ABI) (Pearson -0.454; p = .002) with linear regression indicating the relationship is defined by the formula: Effective ankle brachial index = 1.17 - (1.33 × PVR upstroke ratio at ankle level). A significant negative correlation was also observed between the PVR upstroke ratio and the digital brachial index (Pearson -0.553; p < .001) with linear regression indicating the relationship is defined by the formula: Effective toe brachial index = 1.04 - (1.61 × PVR upstroke ratio at digital level). The results of this investigation demonstrate the feasibility of, and provide equations to approximate, the effective ankle brachial and toe brachial indices in the setting of medial arterial calcification.

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.

Systolic finger pressures during an Allen test before hemodialysis access construction predict severe postoperative hand ischemia.

OBJECTIVE: The Allen test is a simple bedside method for determining hand perfusion. Earlier studies in patients on hemodialysis (HD) found that an Allen test before access construction did not predict hand ischemia later on. The study aimed to assess whether an Allen test combined with finger plethysmography before access surgery has a potential to predict the onset of severe HD access induced distal ischemia (HAIDI). METHODS: Before the first access construction in patients with chronic kidney disease, systolic finger pressures (Pdig, in millimeters of mercury) were obtained using plethysmography at rest and after serial compression of the radial and ulnar artery. A decrease in Pdig (∂Pdig) was calculated as the difference between Pdig-rest and Pdig-compression. The severity of postoperative HAIDI was graded as suggested by a 2016 consensus meeting. Patients with a severe type of HAIDI (grade 2b-4, intolerable pain, invasive treatment required) were compared with controls not having HAIDI. RESULTS: A total of 105 patients with chronic kidney disease (mean age 70 ± 13 years; 65% males) receiving their first access between January 2009 and December 2018 in one center fulfilled study criteria. Ten patients (10%) developed severe HAIDI at 14 ± 5 months after access construction. Before access creation, all patients with HAIDI demonstrated a radial or ulnar dominant hand perfusion pattern compared with just 57% in controls (P = .010). Compression resulted in an almost two-fold greater ∂Pdig in patients with severe HAIDI (51 ± 8 mm Hg vs 27 ± 3 mm Hg; P = .005). A 40-mm Hg ∂Pdig cut-off value demonstrated optimal tests characteristics (sensitivity of 80%, specificity of 77%, positive predictive value of 27%, negative predictive value of 97%) indicating a 10 times greater risk of developing severe HAIDI. CONCLUSIONS: Finger plethysmography quantifying ∂Pdig during an Allen test before access creation may identify patients who have a substantially increased risk of developing severe hand ischemia after HD access surgery.

Basilic vein transposition for unsuitable upper arm hemodialysis needle access segment may attenuate concurrent hand ischemia.

INTRODUCTION: Some hemodialysis patients with a brachial arteriovenous fistula (AVF) have an unsuitable upper arm needle access segment (NAS) necessitating basilic vein transposition (BVT). It was frequently observed that a portion of these patients spontaneously experienced a warmer and less painful dialysis hand after BVT. Aim of this study was to determine whether BVT for an inadequate NAS attenuated hemodialysis access-induced distal ischemia in patients with a brachial AVF. METHODS: Patients with a brachial AVF and an unsuitable NAS also reporting hand ischemia and scheduled to undergo BVT between 2005 and 2016 in a single facility were studied. Hand ischemia was graded as proposed in a 2016 consensus meeting. Hand ischemic questionnaire (HIQ-) scores (0 points, no ischemia-500 points, maximal ischemia), digital brachial index (DBI, ischemia <0.6) and access flow (mL/min) before and after BVT were compared. The cephalic vein and all side branches of the basilic vein were ligated during the BVT. FINDINGS: Ten patients were studied (8 males, 61 [54-75] years). BVT was performed 8 [4-10] months following the initial AVF construction. HIQ-scores dropped from 220 [71-285] to 9 [0-78] (P = 0.043) postoperatively, whereas DBI increased from 0.51 [0.39-0.67] to 0.85 [0.68-0.97] (P = 0.012). DBI and HIQ-scores were inversely correlated (R2 =71%, P = 0.001). Access flows dropped significantly (Flowpre 1120 mL/min [1100-2300] vs. Flowpost 700 mL/min [600-1760]; P = 0.018). Surgery-associated complications were absent and dialysis continued uninterruptedly. Eight patients reported total recovery from hand ischemia six weeks postoperatively. DISCUSSION: Basilic vein transposition for an unsuitable upper arm needle access segment may attenuate hand ischemia in patients with a brachial AVF previously reporting hemodialysis access-induced distal ischemia.

Use of diagnostic modalities for assessing upper extremity vascular pathology.

Vascular pathology of the upper extremity requires consideration of constitutional, anatomic, and functional factors. The medical history and physical examination are essential. The Allen test can be performed alongside a handheld Doppler for arterial mapping. Useful studies include digital-brachial index measurements, digital plethysmography, laser Doppler, and color ultrasounds. Three-phase bone scintigraphy still plays a role in the evaluation of vascularity after of frostbite injury. Angiogram remains the gold standard radiographic instrument to evaluate vascular pathology of the upper extremity, but computed tomography and magnetic resonance scans have an increasing role in diagnosis of vascular pathology.