EAU guidelines on surgical treatment of urinary incontinence.

CONTEXT: The European Association of Urology (EAU) guidelines on urinary incontinence published in March 2012 have been rewritten based on an independent systematic review carried out by the EAU guidelines panel using a sustainable methodology. OBJECTIVE: We present a short version here of the full guidelines on the surgical treatment of patients with urinary incontinence, with the aim of dissemination to a wider audience. EVIDENCE ACQUISITION: Evidence appraisal included a pragmatic review of existing systematic reviews and independent new literature searches based on Population, Intervention, Comparator, Outcome (PICO) questions. The appraisal of papers was carried out by an international panel of experts, who also collaborated in a series of consensus discussions, to develop concise structured evidence summaries and action-based recommendations using a modified Oxford system. EVIDENCE SUMMARY: The full version of the guidance is available online (www.uroweb.org/guidelines/online-guidelines/). The guidance includes algorithms that refer the reader back to the supporting evidence and have greater accessibility in daily clinical practice. Two original meta-analyses were carried out specifically for these guidelines and are included in this report. CONCLUSIONS: These new guidelines present an up-to-date summary of the available evidence, together with clear clinical algorithms and action-based recommendations based on the best available evidence. Where high-level evidence is lacking, they present a consensus of expert panel opinion.

[European Association of Urology guidelines on assessment and nonsurgical management of urinary incontinence]. / Guía clínica de la Asociación Europea de Urología sobre la evaluación y el tratamiento no quirúrgico de la incontinencia urinaria.

CONTEXT: The previous European Association of Urology (EAU) guidelines on urinary incontinence comprised a summary of sections of the 2009 International Consultation on Incontinence. A decision was made in 2010 to rewrite these guidelines based on an independent systematic review carried out by the EAU guidelines panel, using a sustainable methodology. OBJECTIVE: We present a short version of the full guidelines on assessment, diagnosis, and nonsurgical treatment of urinary incontinence, with the aim of increasing their dissemination. EVIDENCE ACQUISITION: Evidence appraisal included a pragmatic review of existing systematic reviews and independent new literature searches, based on Population, Intervention, Comparator, Outcome questions. Appraisal of papers was carried out by an international panel of experts, who also collaborated on a series of consensus discussions, to develop concise structured evidence summaries and action-based recommendations using a modified Oxford system. EVIDENCE SUMMARY: The full version of the guidelines is available online (http://www.uroweb.org/guidelines/online-guidelines/). The guidelines include algorithms that refer the reader back to the supporting evidence, and they are more immediately useable in daily clinical practice. CONCLUSIONS: These new guidelines present an up-to-date summary of the available evidence, together with clear clinical algorithms and action-based recommendations based on the best available evidence. Where such evidence does not exist, they present a consensus of expert opinion.

Review of invasive urodynamics and progress towards non-invasive measurements in the assessment of bladder outlet obstruction.

OBJECTIVE: This article defines the need for objective measurements to help diagnose the cause of lower urinary tract symptoms (LUTS). It describes the conventional techniques available, mainly invasive, and then summarizes the emerging range of non-invasive measurement techniques. METHODS: This is a narrative review derived form the clinical and scientific knowledge of the authors together with consideration of selected literature. RESULTS: Consideration of measured bladder pressure urinary flow rate during voiding in an invasive pressure flow study is considered the gold standard for categorization of bladder outlet obstruction (BOO). The diagnosis is currently made by plotting the detrusor pressure at maximum flow (p(detQmax)) and maximum flow rate (Q(max)) on the nomogram approved by the International Continence Society. This plot will categorize the void as obstructed, equivocal or unobstructed. The invasive and relatively complex nature of this investigation has led to a number of inventive techniques to categorize BOO either by measuring bladder pressure non-invasively or by providing a proxy measure such as bladder weight. CONCLUSION: Non-invasive methods of diagnosing BOO show great promise and a few have reached the stage of being commercially available. Further studies are however needed to validate the measurement technique and assess their worth in the assessment of men with LUTS.

Variation in invasive and noninvasive measurements of isovolumetric bladder pressure and categorization of obstruction according to bladder volume.

PURPOSE: We developed a noninvasive test that provides an estimate of isovolumetric bladder pressure by measuring the pressure required to interrupt voiding using controlled inflation of a penile cuff. We noted variation in serial measurements obtained during a single void and, therefore, we determined whether this represents variation in detrusor contraction strength, as predicted in previous studies, or measurement error. MATERIALS AND METHODS: A total of 36 symptomatic men underwent simultaneous invasive and noninvasive pressure flow studies. Corresponding values of isovolumetric bladder pressure and cuff interruption pressure were recorded at each flow interruption and grouped according to bladder volume to calculate measurement error and bias at various points during a void. Individual variation in the 2 measurements across a range of normalized bladder volumes was then examined using ANOVA. RESULTS: Cuff interruption pressure showed a consistent level of accuracy as an estimate of isovolumetric bladder pressure across a range of volumes. There were similar, statistically significant differences in isovolumetric bladder pressure and cuff interruption pressure recorded at specific volume increments with the highest values seen in the mid range and the lowest seen at lower bladder volumes (each p <0.01). When plotting, the maximum recorded value of cuff interruption pressure in each individual on our proposed noninvasive pressure flow nomogram provided the best diagnostic accuracy for obstruction. CONCLUSIONS: This study shows that cuff interruption pressure varies in the expected manner with bladder volume and provides a consistent estimate of isovolumetric bladder pressure throughout a void. These data provide important guidance for interpreting noninvasive pressure flow studies and classifying obstruction on the proposed nomogram.

A nomogram to classify men with lower urinary tract symptoms using urine flow and noninvasive measurement of bladder pressure.

PURPOSE: Bladder pressure during voiding can be estimated by a noninvasive technique using controlled inflation of a penile cuff. This test provides a valid and reliable estimate of isovolumetric bladder pressure but to our knowledge the role of the test for the routine clinical treatment of patients with lower urinary tract symptoms (LUTS) has yet to be demonstrated. As a first step, we evaluated a proposed nomogram for the diagnosis of bladder outlet obstruction in men with LUTS using noninvasive measurements of pressure and flow. MATERIALS AND METHODS: Using a combination of theoretical calculation and experimental data the existing International Continence Society pressure flow nomogram was modified to allow noninvasive measurement of isovolumetric bladder pressure in place of detrusor pressure at maximum urine flow. Accuracy of the nomogram for classifying obstruction was then tested in a group of 144 men with LUTS who underwent an invasive and a noninvasive pressure flow study. RESULTS: The modified nomogram identified men with obstruction with 68% positive predictive value and 78% negative predictive value. Predictive accuracy could be improved by adding an additional criterion of obstruction, that is maximum urine flow less than 10 ml second, whereby an identifiable 69% of all cases could be classified as obstructed (88% positive predictive value) or not obstructed (86% negative predictive value). In the remaining 31% of patients invasive pressure flow studies would provide additional information, although some results would remain equivocal. CONCLUSIONS: The proposed nomogram combined with the additional flow rate criterion can classify more than two-thirds of cases without recourse to invasive pressure flow studies. We must now evaluate the usefulness of this classification for the treatment of men with LUTS.

An automated penile compression release maneuver as a noninvasive test for diagnosis of bladder outlet obstruction.

PURPOSE: We tested the hypothesis that the previously described penile urethral compression release (PCR) maneuver provides a valid diagnosis of bladder outlet obstruction (BOO) using automated rather than manual penile compression by controlled inflation of a penile cuff. We also investigated urodynamic events underlying generation of the PCR index. MATERIALS AND METHODS: A total of 150 subjects attending for pressure flow studies were studied using conventional and noninvasive cystometry. Patients were classified into urodynamic diagnostic groups using standard invasive studies. The PCR index was calculated for each individual from noninvasive penile cuff data and the results were summarized for each group. ROC analysis of the PCR index was performed to define an optimum threshold for BOO diagnosis. Simultaneous invasive and noninvasive data were used to define the relationship between the PCR index, bladder contractility and the maximum flow rate. RESULTS: The mean PCR index +/- SD was significantly higher in the BOO group compared to the normal cystometry group (215% +/- 84% vs 93% +/- 39, p <0.01). ROC analysis showed that a PCR index of greater than 160% diagnosed BOO with 78% sensitivity, 84% specificity and a positive predictive value of 69%. There was a strong positive correlation between the PCR index and isovolumetric detrusor pressure, which is a measure of bladder contractility (r = 0.44, p <0.01). CONCLUSIONS: The results of this study suggest that the PCR index combines valid estimates of bladder contractility and the maximum flow rate, and it represents a clinically useful, noninvasive urodynamic parameter for the diagnosis of BOO.

Noninvasive measurement of bladder pressure. Does mechanical interruption of the urinary stream inhibit detrusor contraction?

PURPOSE: As part of developing a noninvasive method to measure bladder pressure using an inflatable penile cuff, we tested the hypothesis that detrusor contraction is maintained without inhibition during the test. MATERIALS AND METHODS: Five healthy volunteers and 26 male patients with lower urinary tract symptoms underwent interruption of established urine flow by controlled inflation of a cuff placed around the penis with simultaneous invasive bladder pressure monitoring. After interruption of flow the cuff was rapidly deflated and voiding was allowed to resume. The bladder pressure was recorded before, during and after interruption of flow by cuff inflation. RESULTS: During flow interruption an isovolumetric increase in detrusor pressure was observed. When the cuff was deflated the detrusor pressure quickly returned to preinflation values and urine flow immediately resumed. Intra-abdominal pressure did not change during the cuff inflation cycle. CONCLUSIONS: Mechanical interruption of urine flow by controlled inflation of a penile cuff during voiding does not inhibit detrusor contraction. This finding further validates our noninvasive technique of bladder pressure measurement and supports ongoing studies into its clinical usefulness.

Noninvasive measurement of bladder pressure by controlled inflation of a penile cuff.

PURPOSE: A noninvasive test providing reliable objective quantification of bladder pressure during the voiding cycle would make an important contribution to the management of lower urinary tract symptoms. We developed a new noninvasive test to measure bladder pressure in males based on controlled inflation of a penile cuff during voiding. We compared the new technique with simultaneous invasive bladder pressure measurement. MATERIALS AND METHODS: We evaluated 7 volunteers and 32 patients. A conventional pressure flow study was performed first. The bladder was refilled, a penile cuff was fitted and after voiding commenced the cuff was inflated in steps of 10 cm. water every 0.75 seconds until urine flow was interrupted. The cuff was rapidly deflated, allowing flow to resume, and the cycle was repeated until the end of voiding. The flow rate was graphed against cuff pressure for each interruption cycle to determine the pressure at which flow was interrupted. This pressure was compared with simultaneous invasive isovolumetric bladder pressure. RESULTS: Invasive and noninvasive pressure measurements agreed well. Average cuff pressure at interruption of flow exceeded mean simultaneous isovolumetric bladder pressure plus or minus standard deviation by 14.5 +/- 14.0 cm. water. CONCLUSIONS: The new method provides noninvasive quantitative information on voiding bladder pressure in males. Further study is required to assess whether the technique can contribute to the management of lower urinary tract symptoms.

Transmission of penile cuff pressure to the penile urethra.

PURPOSE: We developed a noninvasive method to measure voiding bladder pressure by inflating a penile cuff to interrupt flow. We tested the underlying assumption that cuff pressure is transmitted to the penile urethra. MATERIALS AND METHODS: In 35 men we simultaneously recorded penile cuff and urethral pressure during 2 experimental protocols for 6 cuffs of various widths and manufactures. Initially a urethral pressure transducer was placed at the mid point of the cuff and urethral pressure was continuously recorded during cuff inflation. In experiment 2 cuff pressure was set at 120 cm. water and the urethral pressure profile was measured by withdrawing the urethral transducer through the cuff width. RESULTS: There was excellent agreement of cuff with urethral pressure over the range of 0 to 200 cm. water for cuffs 37 to 54 mm. wide. Narrower cuffs showed wider variation with less efficient transmission of cuff pressure to the urethral lumen. Similarly maximum pressure in the urethral pressure profile showed best agreement for cuffs 38 and 46 mm. wide. Wider cuffs produced higher and narrower cuffs produced lower transmitted pressure within the urethra. Cuff performance was also related to penile size. Results had good within-subject repeatability. CONCLUSIONS: We demonstrated that pressure transmission from cuff to urethra is optimal at a cuff width of 40 to 50 mm. and recommended this width for other investigations of noninvasive bladder pressure measurement.

A prospective analysis of 1,930 patients with hematuria to evaluate current diagnostic practice.

PURPOSE: The commonly accepted diagnostic algorithm for hematuria includes excretory urography (IVP) and cystoscopy. Some have suggested that ultrasound of the upper urinary tract is adequate and that cystoscopy is not necessary in younger patients with microscopic hematuria. We ascertain whether a less intensive algorithm could be adopted while retaining diagnostic efficacy. MATERIALS AND METHODS: A total of 1,930 patients were enrolled prospectively in the study at a hematuria clinic between October 1994 and March 1997. Evaluation consisted of basic demographics, history and examination, routine blood tests, urinalysis and cytology. All patients underwent plain abdominal radiography, renal ultrasound, IVP and flexible cystoscopy. RESULTS: A total of 1,194 males and 736 females with a mean age of 58 years (range 17 to 96) were included in the study. Overall, 61% of patients had no basis found for hematuria, 12% had bladder cancer, 13% had urinary tract infection and 2% had stones. Kidney and upper tract tumors were noted in 14 patients (0.7%), including 4 who presented with microscopic hematuria. If only ultrasound or IVP had been performed 4 of these cases would have been missed. Of 982 patients presenting with microscopic hematuria 51 had cancer. Bladder cancer was found in 7 patients younger than 40 years. CONCLUSIONS: Our findings suggest that cystoscopy cannot be safely avoided even in younger patients with microscopic hematuria. Only a combination of ultrasound and IVP detected all upper tract tumors.

Transverse retubularized ileum: early clinical experience with a new second line Mitrofanoff tube.

PURPOSE: Transverse retubularization of small ileal segments has been described as a new time and labor saving variation of the Mitrofanoff principle in a dog model with good functional results. We report our initial clinical experience with this technique. MATERIALS AND METHODS: From May 1996 through January 1997 a new technique of channel formation for intermittent catheterization was applied in 9 children (1 to 16 years old) and 7 adults (18 to 56) with various abnormalities of the lower urinary tract. The new method was used in primary reconstruction of the lower urinary tract and in revision procedures. An ileal segment 2 cm. long was excised. The bowel wall was opened longitudinally about 1 cm. from the mesentery. The resulting rectangle was retubularized over a 14F catheter in transverse direction. The longer portion of the tube was implanted submucosally into the native bladder, the augmented bladder or an intestinal reservoir. The shorter portion was used to form the stoma. In 4 patients we created a double tube. RESULTS: Of the patients 13 (81%) are completely continent day and night with easy catheterization postoperatively. In 2 cases of tunnel failure continuous leakage required reimplantation of the intact ileal tube to achieve continence. Minor leakage with bladder fullness in an 11-year-old boy could be obviated by adjusting the interval of catheterization. CONCLUSIONS: With the advantage of constant availability, minimal loss of bowel, relative simplicity (no mesentery interfering with implantation, high tube mobility), minimized risk of stone formation (no staples), reliable continence (no leak point) and easy catheterization (longitudinal folds), this straightforward technique is an excellent second choice use of the Mitrofanoff principle.

Nitric oxide and cyclic GMP formation following relaxant nerve stimulation in isolated human corpus cavernosum.

OBJECTIVE: To investigate further the role of the nitric oxide (NO)-cyclic GMP pathway as the mediator of relaxant neurotransmission in human corpus cavernosum and to establish whether impaired activity of this pathway contributes to the pathophysiology of impotence. PATIENTS AND METHODS: Samples of cavernosal tissue were obtained from 59 men undergoing penile operations. The controls comprised four men with penile carcinoma and 17 with Peyronie's disease. Of the impotent men, 35 had clinical evidence of penile vascular disease on pre-operative investigation, whilst three had non-vascular impotence. Each biopsy was divided into two strips which were then suspended under tension in organ bath chambers. The relaxant innervation of one strip of each pair was stimulated electrically whilst the other strip was left unstimulated. The formation of NO and cyclic GMP was calculated by comparing their respective tissue content in the stimulated and unstimulated strips. RESULTS: Overall, stimulation of the relaxant innervation produced significant increases in the tissue content of both NO and cyclic GMP. Incubation with an inhibitor of NO biosynthesis abolished the mechanical relaxant response and the formation of both NO and cyclic GMP. The magnitude of relaxant response and the formation of NO was diminished in tissue from men with vascular impotence compared to controls. The increase in cyclic GMP content was similar in both these groups. Relaxant response, NO formation and cyclic GMP formation in tissue from men with non-vascular impotence was similar to controls. CONCLUSIONS: This study provides further evidence that the NO-cyclic GMP pathway acts as the mediator of nerve-evoked smooth muscle relaxation in human corpus cavernosum. Diminished NO formation following relaxant nerve stimulation may account for impaired relaxant responses found in tissue from men with vascular impotence and may contribute to the cause of their erectile dysfunction.

The use of duplex ultrasound in the assessment of arterial supply to the penis in vasculogenic impotence.

Impotence may be caused by arterial disease affecting the vessels supplying the corpora cavernosa. Color duplex ultrasound was used to measure the peak systolic velocity and systolic rise time in the deep penile arteries in 22 impotent men following papaverine stimulation. The results were compared with the findings of selective internal pudendal pharmaco-arteriography. A further comparison was made using color duplex ultrasound with 37 impotent men who all responded well to papaverine. A systolic rise time of 110 msec. or more was found to be the best discriminant of disease in the arteries supplying the corpora giving a positive predictive value of 0.92. A long systolic rise time in a papaverine responder may indicate that the arterial supply is borderline or that the arterial flow is maximal and that the problem lies on the sinusoidal-venous side. It appears that in the absence of a pathological condition there is a large surplus arterial supply.

Corpus cavernosal relaxation in impotent men.

OBJECTIVE: To investigate smooth muscle responsiveness in isolated preparations of corpus cavernosum from men with vasculogenic impotence. PATIENTS AND METHODS: Biopsies of corpus cavernosum were obtained from 63 men undergoing penile surgery. These included a control group of eight men (mean age 59 years, range 38-82) undergoing penile amputation for carcinoma, 47 men with vasculogenic impotence (mean age 58, range 36-72) who were further sub-divided into arterial (n = 9), venous (n = 24) or mixed arterial/venous (n = 14) impotence according to the results of pre-operative haemodynamic investigation, and eight men with non-vasculogenic impotence (mean age 49 years, range 34-66). Smooth muscle contractile responses to alpha-adrenoceptor activation and relaxant responses to stimulation of intrinsic nerves and exposure to papaverine and sodium nitroprusside were recorded in tissue strips prepared from the biopsies. Morphology was assessed histologically using haematoxylin and eosin staining of tissue sections together with immunocytochemical labelling of intrinsic nerves. RESULTS: Nerve-evoked relaxation was markedly impaired in tissue from men with venous or mixed arterial/venous impotence. A lesser degree of impairment was found in tissue from men with arterial impotence alone. Tissue from men with all types of vasculogenic impotence also showed a decreased contractile response to alpha-adrenoceptor stimulation. The magnitude of relaxant responses to papaverine and sodium nitroprusside in the vasculogenic group was similar to that of the control. There were no differences in smooth muscle content or nerve density between the vasculogenic group and the control. In the non-vasculogenic group responses to relaxant nerve stimulation, alpha-adrenoceptor activation and relaxant drugs were similar to those of the control. Nerve density in this group was similar to the control but smooth muscle content was reduced. CONCLUSIONS: The results of this study demonstrate a functional impairment of smooth muscle contractility and neurogenic relaxation in corpus cavernosum from impotent men with abnormal penile haemodynamics. Altered smooth muscle responsiveness is likely to be a factor in the aetiology of impotence in such men and may contribute to the relatively poor results of vascular surgery for impotence.

The clinical application of dorsal penile nerve cerebral-evoked response recording in the investigation of impotence.

OBJECTIVE: To determine whether recording of penile cerebral-evoked response (CER) is useful in the assessment of men with impotence. PATIENTS AND METHODS: A total of 280 impotent men underwent CER recording as part of an assessment for a complaint of impotence. They were categorized from findings in the history and examination as having non-neurogenic impotence (n = 106), impotence related to existing neurological disturbance (n = 67), type I diabetes (n = 49) or type II diabetes (n = 58). Increased period of latency or absence of first positive peak (P1) on CER were used as the criteria for an abnormal response with reference to an age-matched control group of potent men (n = 34). RESULTS: Overall, impotent men with diabetes or a history of neurological disturbance had significantly longer P1 latencies and lower response amplitudes compared with the control group. In contrast the CER recorded from men with non-neurogenic impotence was similar to the control group. Individual results showed an increased period of latency or absence of P1 in 100 (36%) impotent men, 72 (72%) of whom were diabetic or had a history of neurological dysfunction. CER abnormalities were associated with neurological signs on physical or cystometrographic examination in 40 (40%) individuals. CONCLUSION: Although technically satisfactory, the clinical usefulness of CER recording is limited by the poor discriminatory value of response latencies. Most abnormal results could be predicted by the presence of diabetes or pre-existing neurological dysfunction, or by evidence of neurological deficit on physical examination. The test is not therefore suitable for routine clinical assessment of impotence but may be worthwhile if objective evidence of penile sensory dysfunction is required.

Evidence against vasoactive intestinal polypeptide as the relaxant neurotransmitter in human cavernosal smooth muscle.

1. The putative role of vasoactive intestinal polypeptide (VIP) as the relaxant neurotransmitter in human cavernosal smooth muscle has been studied in isolated tissue preparations. 2. Consistent neurogenic relaxations were evoked by electrical field stimulation (EFS; 2-64 pulses/train, 0.8 ms pulse duration, 10 Hz). VIP (0.1-3 microM) relaxed cavernosal smooth muscle in a dose-dependent fashion. Relaxant responses to both EFS and VIP were reduced in tissue from impotent men. 3. Neurogenic relaxant responses were not diminished in the presence of the VIP-inactivating peptidase, alpha-chymotrypsin (alpha-CT, 2 units ml-1). In contrast VIP-induced relaxations were completely abolished. 4. Inhibition of nitric oxide synthase by NG-nitro-L-arginine (30 microM), and of guanylate cyclase by methylene blue (50 microM) caused highly significant reductions of neurogenic relaxant responses whereas VIP-evoked relaxations were unaffected. 5. It is concluded that VIP-evoked relaxations are not mediated by the NO-guanosine 3':5'-cyclic monophosphate (cyclic GMP) pathway and that VIP release is not essential for neurogenic relaxation of human cavernosal smooth muscle. VIP does not therefore act as the major relaxant neurotransmitter in this tissue.

The effect of inhibitors of nitric oxide biosynthesis and cyclic GMP formation on nerve-evoked relaxation of human cavernosal smooth muscle.

1. The inhibitory transmission in isolated preparations of cavernosal smooth muscle from human penis has been studied. 2. Electrical field stimulation (EFS; 2-64 pulses/train, 0.8 ms pulse duration, 10 Hz) evoked relaxation of preparations treated with guanethidine (50 microM). The EFS-evoked relaxations were atropine-resistant and tetrodotoxin-sensitive indicating their origin to be non-adrenergic, non-cholinergic (NANC) nerve stimulation. 3. EFS-evoked relaxation was attenuated dose-dependently by the nitric oxide (NO)-synthase inhibitor, L-NG-nitro arginine (L-NOARG; 0.3-100 microM) but not by D-NG-nitro arginine. The inhibitory effect of L-NOARG on transmission was antagonized by L-arginine (100 microM), a NO precursor, but not by D-arginine. 4. Incubation with methylene blue (10-50 microM), a known inhibitor of guanylate cyclase activation by NO, caused a concentration-related inhibition of EFS-evoked relaxation. 5. It is concluded that NANC nerve-evoked relaxation of human cavernosal smooth muscle is mediated by NO or a NO-like substance.

The role of colour duplex ultrasonography in the diagnosis of vasculogenic impotence.

Colour duplex ultrasonography was used to obtain peak systolic velocity (PSV) readings from cavernosal arteries at rest and during papaverine-induced tumescence. Results from 31 men with vasculogenic impotence were compared with those from 17 men with non-vasculogenic impotence and a control group of 6 potent men. In the flaccid state no significant differences in PSV readings were found between the vasculogenic and control groups. Following the injection of papaverine, men from the vasculogenic group without venous leakage were alone in having significantly lower PSV readings compared with the potent controls. All 23 men with normal penile haemodynamics had a mean PSV greater than or equal to 20 cm/s during tumescence. This was also the case for 19 (61%) of the vasculogenic group, including 9 (69%) of the 13 patients with venous leakage. The remaining 12 men in the vasculogenic group (39%) had a mean PSV less than 20 cm/s, this being diagnostic of an inadequate arterial inflow. Colour duplex ultrasonography can identify patients who have marked arterial insufficiency as the major cause of their impotence and hence allows more rational selection for angiography and revascularisation. Lesser degrees of arterial deficit are difficult to characterise using mean PSV readings alone.