Modified Allen Test Research Articles

Prevalence of The Arterial Hand Dominance Using the Modified Allen Test and Pulse Oximetry among Plastic Surgery Patients.

The ulnar and radial arteries are the major source of blood supply in the hand, as they form the superficial and deep palmar arches. Arterial hand circulation is one of the most complicated arterial trees and connections in the body, with tremendous variations in its structure. This study aimed to evaluate whether the ulnar artery or radial artery is the dominant artery in hand circulation among plastic surgery patients at King Khalid University Hospital and to correlate the arterial hand dominance with handedness and gender. This is an analytical cross-sectional study conducted at King Khalid University Hospital in Riyadh, Saudi Arabia, on plastic surgery patients. The sampling method is purposive sampling. The calculated sample size is 28; however, 100 participants have been enlisted in the study. The data have been collected using the modified Allen test with a pulse oximeter. The collective prevalence of dual arterial dominance in our study was 69% compared with 56% and 30% for Little et al (P = 0.013) and Fuhrman et al (P < 0.001), respectively. With regard to gender, women were more likely to have a dual arterial blood supply than men, with the frequency values of 85% and 58.3% for women and men, respectively (P = 0.017). Our study found that dual arterial supply is predominant among our participants, with 69% of our participants possessing a dual arterial supply, while 18% and 13% constitute the prevalence of radial and ulnar dominance, respectively. This contrasts with what has been reported previously in the literature.

To compare the frequency of first attempt successful ultrasound guided radial artery cannulation by modified short axis out-of-plane technique versus conventional long axis in-plane technique.

Objective: To compare the frequency of first attempt successful ultrasound guided radial artery cannulation by modified short axis out-of-plane technique versus conventional long axis in-plane technique. Study Design: Quasi Experimental Study Setting: Jinnah Hospital, Lahore. Study Period: 1st January 2019 to 30th June 2019. Material &amp; Methods: 180 patients fulfilling the selection criteria were divided in two groups using lottery method. Group modified SA-OOP (short axis out-of-plane) and group LA-IP (long axis in-plane). Modified Allen test was performed in all patients, if positive, procedure was carried out. In modified short axis out of plane approach, a suture was tied on the midpoint of ultrasound probe and perpendicular to the long axis as a guide and then radial artery was viewed by placing US probe on the wrist of patient transversely. The needle was inserted at 30⁰-45⁰ angle into the skin. In long Axis In- Plane approach, radial artery was first viewed by placing US probe transversely on the wrist of patient and then probe was rotated to 90⁰ in clockwise direction to see the artery in longitudinal plane. Then cannula was inserted at 30⁰-45⁰ angle into the skin. Success of first attempt was recorded. Results: The age range was 18-70 years. Mean age of the patients was 46.69 ± 17.35 and 43.68 ± 17.99 years in group LA-IP and SA-OOP, respectively (4). In group LA-IP, 57 patients (63.3%) were male and in group SA-OOP 45 patients (50%) were male while 33 patients (36.7%) of group LA-IP and 45 patients (50%) of group SA-OOP were female. Frequency of first attempt was 64.4% (58 patients) in group LA-IP and in group SA-OOP frequency of first attempt was 53.3% (48 patients). Statistically significant difference was not seen between two groups as p-value is 0.172. Conclusion: There is no difference in frequency of first attempt success in modified short axis out-of-plane ultrasound versus conventional long axis in-plane ultrasound to guide radial artery cannulation.

Modified Allen Test Assessment via Imaging Photoplethysmography

Abstract The modified Allen test (MAT) is a widely used tool to examine the perfusion capacities of the arteries (ulnar or radial) of the hand. In clinical practice, MAT is utilized to ensure that in the event of occlusion, remaining vessels guarantee sufficient hand perfusion. This work shows that perfusion assessment via imaging photoplethysmography (iPPG) can be used to assess MAT. We captured the hands of seven subjects with a standard RGB camera while performing a MAT. Out of these captured video recordings, the iPPG signal was extracted via plane-orthogonal-to-skin transformation. Based on these extracted signals, we derive the heart rate, signal-to-noise ratio, DC parameter, and correlation with a reference iPPG signal to determine if an Allen test was pathological or inconspicuous. For all seven subjects, the results of our MAT assessment were identical to the medical expert’s assessment. This paper presents a procedure and initial thresholds for objectively evaluating and quantifying MAT.We show how globally and locally calculated parameters can be used to assess the perfusion of the investigated hand. This analysis makes it possible to quantify the exact point in time when the perfusion is again sufficient. If a reperfusion problem occurs, we are able to localize the spatial regions of occurrence. The presented hardware setup is affordable and can be easily installed and used in every doctor’s office.

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

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 (Pdig) 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 (∂Pdig) during a preoperative MAT and mortality after a first HD access construction. Pdig (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 ∂Pdig 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 ∂Pdig and mortality. 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 ∂Pdig was 31 mmHg (range 0-167 mmHg). Patients having cardiovascular disease (CV+) demonstrated higher ∂Pdig 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 ∂Pdig 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, ∂Pdig remained associated with CV+ mortality (HR 1.13 [1.00-1.26], p = 0.043). 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.

The modified Allen test and a novel objective screening algorithm for hand collateral circulation using differential photoplethysmography for preoperative assessment: a pilot study

Hand-ischemia and artery-thrombosis are serious complications of hand artery cannulation/grafting. Screening the patency of hand arteries reduces the complications. Modified Allen Test (MAT), Barbeau's test, and Doppler/Duplex-ultrasonic test screen hand arterial patency. Each of them, however, either lacks objectivity, requires subject cooperation, or is not readily available in operating rooms. In this pilot study, we aim to provide a novel, objective, reliable, and inexpensive alternative using differential photo-plethysmography (PPG) measurement, and an artery selection algorithm. For 11 participants, MAT was executed, and PPG measurements of the thumb and little fingers were recorded for left and right hands separately. For each hand, four evaluations were conducted, then fed into the artery selection algorithm. Our proposed procedure has shown congruent results with the anatomy of blood circulation. It identified two arteries in two participants causing >50% blood reduction in the hand due to their occlusion. It also showed an elevated risk of accessing an artery in another 8 participants. Once the results of this study are confirmed in larger samples, the proposed procedure/algorithm may provide many indicators of the hand blood circulation, the effect of an artery occlusion on the hand, and a recommendation for selecting the best artery to access with the lowest possible complications.

Photoplethysmography using a smartphone application for assessment of ulnar artery patency: a randomized clinical trial.

Radial artery access is commonly performed for coronary angiography and invasive hemodynamic monitoring. Despite limitations in diagnostic accuracy, the modified Allen test (manual occlusion of radial and ulnar arteries followed by release of the latter and assessment of palmar blush) is used routinely to evaluate the collateral circulation to the hand and, therefore, to determine patient eligibility for radial artery access. We sought to evaluate whether a smartphone application may provide a superior alternative to the modified Allen test. We compared the modified Allen test with a smartphone heart rate-monitoring application (photoplethysmography readings detected using a smartphone camera lens placed on the patient's index finger) in patients undergoing a planned cardiac catheterization. Test order was randomly assigned in a 1:1 fashion. All patients then underwent conventional plethysmography of the index finger, followed by Doppler ultrasonography of the radial and ulnar arteries (the diagnostic standard). The primary outcome was diagnostic accuracy of the heart rate-monitoring application. Among 438 patients who were included in the study, we found that the heart rate-monitoring application had a superior diagnostic accuracy compared with the modified Allen test (91.8% v. 81.7%, p = 0.002), attributable to its greater specificity (93.0% v. 82.8%, p = 0.001). We also found that this application had greater diagnostic accuracy for assessment of radial or ulnar artery patency in the ipsilateral and contralateral wrist (94.0% v. 84.0%, p < 0.001). A smartphone application used at the bedside was diagnostically superior to traditional physical examination for confirming ulnar patency before radial artery access. This study highlights the potential for smartphone-based diagnostics to aid in clinical decision-making at the patient's bedside. Trial registration: Clinicaltrials.gov, no. NCT02519491.

The ACRA Anatomy Study (Assessment of Disability After Coronary Procedures Using Radial Access): A Comprehensive Anatomic and Functional Assessment of the Vasculature of the Hand and Relation to Outcome After Transradial Catheterization.

The palmar arches serve as the most important conduits for digital blood supply, and incompleteness may lead to digital ischemia when the radial artery becomes obstructed after cardiac catheterization. The rate of palmar arch incompleteness and the clinical consequences after transradial access are currently unknown. The vascular anatomy of the hand was documented by angiography in 234 patients undergoing transradial cardiac catheterization. In all patients, a preprocedural modified Allen test and Barbeau test were performed. Upper-extremity function was assessed at baseline and 2-year follow-up by the QuickDASH. Incompleteness of the superficial palmar arch (SPA) was present in 46%, the deep palmar arch was complete in all patients. Modified Allen test and Barbeau test results were associated with incompleteness of the SPA (P=0.001 and P=0.001). The modified Allen test had a 33% sensitivity and 86% specificity for SPA incompleteness with a cutoff value of >10 seconds and a 59% sensitivity and 60% specificity with a cutoff value of >5 seconds. The Barbeau test had a 7% sensitivity and 98% specificity for type D and a 21% sensitivity and 93% specificity for types C and D combined. Upper-extremity dysfunction was not associated with SPA incompleteness (P=0.77). Although incompleteness of the SPA is common, digital blood supply is always preserved by a complete deep palmar arch. Preprocedural patency tests have thus no added benefit to prevent ischemic complications of the hand. Finally, incompleteness of the SPA is not associated with a loss of upper-extremity function after transradial catheterization.

Clinical audit and national survey on the assessment of collateral circulation before radial forearm free flap harvest.

Controversy exists regarding the use of Duplex Ultrasound (DUS) in addition to the Modified Allen's Test (MAT) for the assessment of collateral circulation prior to elevation of the Radial Forearm Free Flap (RFFF). A survey amongst members of BAOMS Head & Neck Oncology Subspecialty Interest Group and a completed local audit was undertaken to assess the need for DUS. Data for the initial audit was collected retrospectively between 2010 and 2013. Both MAT and DUS was performed routinely during this period. The results of the survey and initial audit led to a change in practice and DUS was no longer requested. The re-audit was performed prospectively between 2013 and 2015. The results of the survey showed that all respondents performed MAT. DUS was performed 'always' by 40%, 'sometimes' by 13.3% and 'never' by 46.7%. A total of 41 patients were included in the initial audit, 6 had an abnormal DUS but only 1 had an abnormal MAT. Five cases had an abnormal DUS but normal MAT and went on to have their ipsilateral RFFF raised without ischaemic complications. The patient with an abnormal MAT had their contralateral RFFF raised. No patients suffered ischaemic complications during the initial audit. A total of 48 patients were included in the re-audit 2 of which had an abnormal MAT and their contralateral RFFF raised. No patients suffered ischaemic complications during the re-audit. In conclusion, routine use of DUS did not provide any additional information above the MAT in identifying patients at risk of ischaemic complications.

Is radial artery Doppler scanning mandatory for use as coronary bypass conduit?

Screening of the radial artery prior to harvesting as a conduit for coronary bypass may be performed clinically by the Allen test or by Doppler ultrasound. In a developing country like ours, the use of resources for Doppler studies may be questioned when Allen tests lead to a low rate of clinical sequelae. However, the rare occurrence of hand ischemia may be devastating and could justify the routine use of Doppler screening. This study aimed to address this question. One hundred patients undergoing elective coronary artery bypass grafting were screened by the modified Allen test and Doppler ultrasound for suitability of use of a radial artery conduit. After harvesting, proximal and distal segments of the radial artery were subjected to histopathological examination. Of the 95 patients deemed suitable for radial artery grafting, 6 had mild calcification on Doppler ultrasound and 9 had calcification on histopathological examination. While Doppler showed atherosclerosis in 9 patients, only 6 had histopathological evidence of this (false-positive rate 3%). Of the 6 patients with histopathologic evidence of atherosclerosis, 2 were negative on Doppler (false-negative rate 2%). Routine preoperative Doppler screening of the radial artery in the setting of limited resources is not justified. On the other hand, the time-tested Allen test which is easy to perform, interpret, and reproduce can be safely used as the sole screening test to harvest the radial artery.

CRT-173 Is the Allen Test Necessary Before Transradial Artery Catheterization?

We investigated whether Allen test is necessary before transradial approach. Transradial approach has been feasible and effective for cardiac and other vascular interventions in recent years. Most operators use a modified Allen test due to known collateral circulation in the hand; however, the

The Effects of Different Type Vasodilator Agents on Radial Artery Blood Flow: A Placebo-Controlled Clinical Study

Background: The radial artery (RA) is being used as a second arterial conduit in coronary artery bypass grafting (CABG) patients. Vasospasm during the harvesting is the most common problem, yet. Our goal of this research is to evaluate the effects of different vasodilators on RA blood flow. Material and Method: In our 250 CABG patients who were included into the study, patients were divided into five groups which have the same number of the patients. Before the harvesting of the RA, Allen test and modified Allen test were performed. In group 1, sodium nitroprusside (SNP) was administered via central line. In group 2, nitrogliceryne was applied as a vasodilator agent. In group 3, diltiazem as a calcium channel blocker was used. In group 4, dobutamine was used with a dose of 3micro./kg/min. In the remaining patients, as a control group (CG), normal saline solution was used with the same protocol. RA length and radial artery flow, mean arterial blood pressure, central venous pressure, and heart rate were measured before and 10 minutes after drug administration. Results: No significant differences were found between the groups in respect to age, body surface area, cardiopulmonary bypass time, aortic cross clamp time. A multivariate general linear model was created and revealed the drug (specifically SNP and nitroglycerin) as a predictor to increase flow in the radial artery (p = 0.001 and p = 0.002), respectively. SNP has significantly decreased mean arterial pressure when we compared to nitroglycerin (p 0.05). Conclusions: Our study showed that SNP and nitroglycerin are very effective agents to provide the increasing of RA blood flow. However, statistical comparisons exhibited that intravenous SNP was a very effective vasodilating agent for RA than nitroglycerin.

Faut-il encore faire le test d’Allen chez les patients devant avoir une voie d’abord transradiale pour un cathétérisme cardiaque ?

The last decade has seen an increasing use of the radial artery access for coronary angiography as it combines low rates of vascular complications and early mobilization. Since its description by Campeau the percutaneous transradial access was associated with low rates of occlusion but although the incidence of ischemia is uncommon, consequences can be disastrous. That's why assessment of collateral circulation of the hand is required. Traditionally the modified Allen test was used as a tool to assess palmar arch collaterals but no consensus exists about its proper role. So the purpose of our review is to see if the modified Allen test can predict ischemic complications of the hand and if it still should be done.

Recanalization of a Chronic Radial Artery Occlusion Allowing Subsequent Complex Coronary Intervention

A 65-year-old man with previous coronary artery bypass grafting and recent recurrence of angina was referred for coronary angiography. His medical history included myelodysplasia with significant anemia (hemoglobin, 7.7 g/dL) and thrombocytopenia (platelets, 77×10 9 /L). A percutaneous coronary intervention was performed 4 years previous to an occluded native right coronary artery via the left radial artery. Given the increased risk of bleeding complications and a patent left internal mammary artery graft, coronary angiography was planned again via the left radial artery. The result of a modified Allen test was positive, demonstrating satisfactory ulnar arterial supply to the hand. Arterial puncture using a SURFLO micropuncture needle (Terumo Medical Corporation; Somerset, NJ) resulted in pulsatile blood flow back, but it proved impossible to advance the 0.021-inch introducer wire more than a few centimeters into the vessel. Therefore, the cannula on the introducer needle was advanced over the wire to secure arterial access and radial angiography was performed, which demonstrated radial artery occlusion (RAO; Figure 1; online-only Data Supplement Movie I). The occlusion was not believed to …

Arterial Puncture for Blood Gas Analysis

Puncture of the radial artery is the preferred method of obtaining an arterial blood sample for blood gas analysis. The chief indication for blood gas analysis is the need to obtain values for the partial pressures of oxygen and carbon dioxide and for arterial pH. This information is needed in assessing a patient with acute, severe respiratory distress. Measurements of arterial pH and the partial pressures of carbon dioxide and oxygen provide accurate information on the status of acid–base balance and gas exchange. Another indication for arterial blood gas sampling is the need to perform CO-oximetry in order to assess for methemoglobinemia and carboxyhemoglobinemia. Contraindications Radial arterial puncture is contraindicated in the presence of a known deficiency of collateral circulation to the distal upper extremity. A modified Allen test can be performed to assess the adequacy of the collateral circulation of the radial artery by the ulnar artery (Fig. 1). To perform the test, occlude both the ulnar and radial arteries. Instruct the patient to make a fist to drain the blood from the hand; this should be done for approximately 30 seconds. Instruct the patient to unclench the fist. The patient’s palm should appear blanched or pale. Now, release pressure only from the ulnar artery. Adequate collateral circulation is indicated by the return of normal color within 10 seconds. 1 There is no agreement as to whether the Allen test can accurately predict the risk of rare ischemic complications. 2 On the basis of current evidence, its use can be neither refuted nor supported. Alternative techniques to measure collateral circulation of the forearm include color Doppler studies of flow, plethysmography, and magnetic resonance imaging. 3 These methods are more often used in assessing the radial artery for more invasive procedures, such as arterial harvesting for coronary bypass. Radial arterial puncture should not be performed in patients with an overlying skin infection. In patients who are taking anticoagulants or in those with coagulopathies, it should be performed only if absolutely necessary, because of the increased risk of bleeding and hematoma formation. Preparation Standard kits for sampling arterial blood gas are readily available and should contain a syringe, a small 23-to-25-gauge needle (either with a rubber stopper used to remove the needle from the syringe or with an attached safety cap), and a syringe cap containing dry lithium heparin or sodium heparin. The concentration of hepa

The morphometry and eNOS expression of radial artery in elderly patients with coronary atherosclerotic heart disease

To compare the morphometry and endothelial nitric oxide synthase (eNOS) expression of radial artery (RA) between young and elderly patients with coronary atherosclerotic heart disease. From February 2008 to June 2009, 219 patients underwent coronary artery bypass grafting (CABG) with autologous RA, 57 patients aged beyond 70 years and 64 patients aged under 60 years. Before RA was harvested, a modified Allen test was routinely performed. If positive, RA would be further evaluated with Doppler ultrasound examination. In both groups RA was collected for HE staining to evaluate percentage of luminal narrowing (LN) and relationship between intima and media width at maximum intimal thickness (IMR). Immunofluorescence and Western blot were used to investigate the location and expression level of eNOS within the wall of RA. Morphometry of RA in both young and elderly patients represented mild or moderate intimal hyperplasia, and medial calcification was not found. LN in elderly patients was (22 ± 6)%, while in young patients, it was (23 ± 6)%. IMR in elderly patients was 0.36 ± 0.21, while in young patients, it was 0.42 ± 0.19. There was no significant difference in both LN and IMR between two groups (P > 0.05). Immunofluorescence indicated RA in both groups revealed a high expression of eNOS in intima and media, particularly in the smooth muscle of media. The values of relative integrated optical density in elderly patients was 1.21 ± 0.13, while in young patients, it was 1.25 ± 0.12. Also there was no significant difference in the expression level of eNOS within the wall of RA (P > 0.05). After preoperative assessment with modified Allen's test and Doppler analysis, RA used as graft in the elderly has similar quality and function with young patients, and it may lead to a high patency in long term.

Radial Artery Harvesting for Coronary Artery Bypass Grafting: A Stepwise-Made Decision

The purpose of this study was to propose a safe, stepwise, testing system to select radial arteries that are suitable for conduits on the basis of their morphologies and characteristics of the collateral circulation. Before operation, 113 patients underwent the modified Allen test, Doppler ultrasonography, and pulse oximetry testing. Morphologic criteria used for radial artery exclusion were small size of radial or ulnar artery (< 2 mm in inner diameter), diffuse calcifications, and congenital anomalies of forearm arteries. Collateral circulation was interpreted as insufficient if the reverse flow in the anatomic snuffbox was absent or if the increase of the ulnar peak systolic flow velocity was less than 20%. A positive modified Allen test was found in 10.6% of patients. As assessed by Doppler ultrasonography, 27 patients (23.9%) were not candidates for radial artery harvesting according to morphologic and functional abnormalities of forearm and hand circulation. Pulse oximetry test results were abnormal in 6.2%. After a follow-up period of 8.9 +/- 1.8 months, 23 patients (29.1% of operated patients) were controlled for Doppler ultrasonographic changes in the ulnar artery. The mean peak systolic flow velocity was significantly higher than the preoperative value measured at rest (p < 0 .001). After preoperative tests, including the modified Allen test, Doppler ultrasonography, and pulse oximetry, 30.1% of patients were not considered candidates for radial artery harvesting. This method provides preoperative radial artery selection according to its morphologies, compensatory capacity of collateral circulation, and anatomic properties of ulnar artery.

Ultrasound-Guided Radial Artery Catheterization and the Modified Allen's Test

In this case report, ultrasound-guided radial artery catheterization and a modified Allen's test were performed by Emergency Department (ED) physicians to facilitate the management of an intubated, critically injured patient. Ultrasound was demonstrated to be a valuable tool in determining collateral circulation and guiding radial artery cannulation in a patient unable to cooperate with the traditional Allen's test. Ultrasound guidance may reduce the risk of radial artery catheterization in severely injured patients.

Comparison of Ultrasonically Activated Scalpel and Traditional Technique in Radial Artery Harvesting: Clinical Research

Use of the radial artery (RA) as a conduit in coronary artery bypass grafting (CABG) has become increasingly popular in recent years. The aim of this study was to compare the results of two different RA harvesting techniques. Use of the harmonic scalpel is suggested to be safe and additionally reduces spasm rates. From January 2000, the first 200 consecutive patients who underwent RA harvesting for CABG were enrolled in this study. Patients were divided into two groups. RA was harvested by means of electrocautery + hemoclips in Group I and by harmonic scalpel + hemoclips in Group II. 30 patients (30 %) in Group I and 25 patients (25 %) in Group II were female. Mean age was 53.9 +/- 9.3 and 53.5 +/- 8.4 years in Group I and Group II, respectively. Hand circulation and ulnar collateral flow was assured with a modified Allen test in all patients preoperatively. During the operation perfusion of the hand was monitored by oximetric plethysmography. The distal end of RA was also explored and clamped with a soft vascular clamp to evaluate the saturation values in the groups. During the clamping period, oxygen saturation values did not decrease so we harvested RAs in all patients. There were no statistically significant differences between the groups with the exception of the RA harvesting times, the postoperative analgesia requirements, the rate of vasospasm and the need for hemostatic clips. Harmonic scalpel usage in RA harvesting causes less trauma to adjacent tissues; the analgesia requirements, the rate of vasospasm, the RA harvesting time and the need of hemostatic clips decreases. We conclude that the use of a harmonic scalpel for radial artery harvesting is safer and faster than the routine technique.

Can the modified Allen's test always detect sufficient collateral flow in the hand? A computational study

Blood flow in the largest arteries of the arm up to the digital arteries is numerically modelled using the one-dimensional equations of pressure and flow wave propagation in compliant vessels. The model can be applied to different anatomies of arterial networks and can simulate compression of arteries, these allowing us to simulate the modified Allen's test (MAT) and to assess its suitability for the detection of sufficient collateral flow in the hand if radial blood supply is interrupted. The test measures blood flow in the superficial palmar arch before and during compression of the radial artery. The absence of reversal flow in the palmar arch with the compression indicates insufficient collateral flow and is referred to as a positive MAT. This study shows that small calibres of the superficial palmar arch and insufficient compression of the radial artery can lead to false-positive results. Measurement of the drop in digital systolic pressures with compression of the radial artery has proved to be a more sensitive test to predict the presence of sufficient ulnar collateral flow in networks with small calibres of the superficial palmar arch. However, this study also shows that digital pressure measurements can fail in detecting enough collateral flow if the radial artery is insufficiently compressed.

A morphometric study on the superficial palmar arch of the hand

The vascular anatomy of the hand is a complex and challenging area and has been the subject of many studies. Knowledge of the vascular patterns and diameters of the hand gained more importance with improvements in microsurgical techniques in reconstructive hand surgery. We evaluated 50 hands (26 left, 24 right) of 26 formalin preserved cadavers to determine the superficial palmar arch, its branches and contributing vessels with special attention to the diameters. The symmetry of the types was also evaluated in detail for the first time in the literature. Measurements were made with the help of a digital caliper. The diameters of the ulnar, radial and median arteries were taken at the level of the wrist while the common palmar digital arteries, hypothenar branches and the superficial palmar branch of the radial artery were measured at their origin. Two types of superficial palmar arch were found and defined as complete (43/50 hands) and incomplete arches (7/50 hands). The complete arches were divided into four subgroups and incomplete arches into three subgroups. Most cases were found at the complete AI group (17 hands). Comparison of the arterial diameters showed the ulnar artery was the dominant vessel of the palm. The diameters of the common palmar digital arteries were not different with regard to complete or incomplete arches and between both sides. It looks safe to sacrifice one of the radial or ulnar arteries in some arterial interventions including radial artery cannulation, radial forearm flap and radial or ulnar artery harvesting for bypass grafting if the arch is complete. But we still recommend the noninvasive tests like modified Allen test or Doppler ultrasonography, before performing an invasive arterial intervention. We propose the radiologists to incorporate the median artery into the Doppler dynamic test in particular the existence or the absence of anastomoses between radial and ulnar arteries.