Resistive Index of Prostate Capsular Arteries: A Newly Identified Parameter to Diagnose and Assess Bladder Outlet Obstruction in Patients with Benign Prostatic Hyperplasia

Correlation of resistive index of prostatic capsular artery to clinical symptoms in men with chronic prostatitis/chronic pelvic pain syndrome

OBJECTIVES

To evaluate the relation between resistive index (RI) of prostatic capsular arteries by transrectal Doppler ultrasonography in chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and its correlation with lower urinary tract symptoms, erectile dysfunction and premature ejaculation parameters of CP/CPPS.

METHODS

In total, we included 68 patients presenting with chronic prostatitis/chronic pelvic pain syndrome. We formed two groups, as Group 1 of 35 patients with a RI ≥ 0.7 and Group 2 of 33 patients with RI < 0.7. All patients were assessed with International Prostate Symptom Score (IPSS), International Index of Erectile Function (IIEF-5), premature ejaculation diagnostic tool (PEDT) and National Institutes of Health Chronic Prostatitis Symptom Index (CPSI). In addition, the RI of the prostate capsular artery was measured in all patients using Doppler ultrasound. Statistical analyses were performed with SPSS version 18. A p value < .05 was considered significant.

RESULTS

Demographic characteristics were similar in the two groups. IPSS was 11.3 ± 6 in Group 1 and 9.7 ± 5.3 in Group 2. IIEF-5 was 18.6 ± 2 in Group 1 and 20.4 ± 2.3 in Group 2. PEDT was 12.4 ± 5.6 in Group 1 and 11.2 ± 4 in Group 2. CPSI (total) was 19.3 ± 12.3 in Group 1 and 10.6 ± 7.7 in Group 2. There was significant statistical difference in IPSS, IIEF-5, and CPSI between the two groups (p < .001, p < .001, p < .001 respectively). However, we found no significant difference in PEDT between the two groups (p = .19).

CONCLUSIONS

There is a significant correlation between the lower urinary tract symptoms and erectile dysfunction parameters and the RI of the prostatic capsular artery in CP/CPPS and RI is an effective and noninvasive method to assess the severity of the disease.

The diagnostic value of non-invasive methods for diagnosing bladder outlet obstruction in men with lower urinary tract symptoms: A meta-analysis

Purpose

We conducted the first meta-analysis to determine the diagnostic value of non-invasive methods for diagnosing bladder outlet obstruction (BOO) in men with lower urinary tract symptoms (LUTS).

Methods

We searched a range of databases for relevant publications up to June 2022, including PubMed, Embase, Web of Science, and the Cochrane Library. Retrieved studies were then reviewed for eligibility and data were extracted. The risk of bias (RoB) was assessed using the QUADAS-2 tool. We then performed a formal meta-analysis to evaluate the accuracy of various non-invasive methods for diagnosing BOO in men.

Results

We identified 51 eligible studies including 7,897 patients for meta-analysis. The majority of the studies had a low overall RoB. Detrusor wall thickness (DWT) (pooled sensitivity (SSY): 71%; specificity (SPY): 88%; diagnostic odds ratio (DOR): 17.15; area under curve (AUC) 0.87) and the penile cuff test (PCT) (pooled SSY: 87%; SPY: 78%; DOR: 23.54; AUC: 0.88) showed high accuracy for diagnosing BOO. Furthermore, data suggested that DWT had the highest pooled SPY (0.89), DOR (32.58), and AUC (0.90), when using 2 mm as the cut-off.

Conclusion

Of the non-invasive tests tested, DWT and PCT had the highest levels of diagnostic accuracy for diagnosing BOO in men with LUTS. DWT, with a 2 mm cut-off, had the highest level of accuracy. These two methods represent good options as non-invasive tools for evaluating BOO in males.

Evaluation of resistive index of the prostate and bladder sonomorphologic parameters as replacements for urodynamics to predict bladder outlet obstruction in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia

OBJECTIVE

This study investigated whether the resistive index (RI) of prostate and bladder sonomorphologic parameters (total prostate volume [TPV], detrusor wall thickness [DWT], intraprostatic protrusion [IPP]) can be used instead of urodynamic studies (UDS) to predict bladder outlet obstruction (BOO) in benign prostatic hyperplasia (BPH) with lower urinary tract symptoms (LUTS).

METHODS

Men aged ≥50 years with clinical BPH/LUTS were prospectively enrolled included. Basic evaluations, measurement of sonomorphologic parameters, and UDS were performed in accordance with the International Continence Society's Good Urodynamics Practices protocol.

RESULTS

Data of 240 patients were divided into two groups based on the BOO index(BOOI). Group 1 consisted of patients negative for BOO (BOOI <40), whereas Group 2 consisted of patients positive for BOO (BOOI > 40). Patient age, International Prostate Symptom Score (IPSS), quality of life score and post-void residual volume were comparable between the two groups, whereas significant differences were evident in peak flow rate, TPV, DWT, RI, and IPP (P < 0.01 for all). Pearson correlation analysis revealed a significant correlation between BOOI and DWT (r = 0.198, P = 0.002), IPP (r = 0.450, P = 0.000), and RI (r = 0.334, P = 0.000). Multiple regression analysis revealed a significant correlation between BOOI and IPP (β = 0.382, P = 0.000) and RI (β = 0.226, P = 0.000). Receiver operating characteristic analysis showed that the area under curve was 0.785 for RI (95% confidence interval [CI] 0.703-0.867, P < 0.001) and 0.905 for IPP (95% CI 0.850-0.961, P < 0.001). At a cut-off value of 7.5 mm for IPP, the sensitivity was 86.9%, specificity was 83.3% and positive predictive value was 92.41%.

CONCLUSION

IPP and RI may be the best non-invasive predictors for BOO in selected patients with LUTS/BPH.

Non-invasive evaluation of lower urinary tract symptoms (LUTS) in men

Lower urinary tract symptoms (LUTS) are common in males over the age of 40 years old and are likely to increase with an aging population. Currently urodynamic studies are the gold standard to determine the aetiology of voiding dysfunction and LUTS. However, due to its invasive nature, a great number of non-invasive ultrasound based investigations have been developed to assess patients with symptomatic LUTS. The clinical application of non-invasive tests could potentially stratify patients who would require more invasive investigations and allow more precise patient directed treatment. A PubMed literature review was performed and we will discuss the non-invasive investigations that have been developed thus far, focusing on bladder wall and detrusor wall thickness (BWT & DWT), ultrasound estimated bladder weight (UEBW) and intravesical prostatic protrusion (IPP).

Combination of intravesical prostatic protrusion and resistive index is useful to predict bladder outlet obstruction in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia

OBJECTIVES

To examine which parameters obtained from transrectal ultrasonography are accurate predictors of urodynamically-confirmed bladder outlet obstruction in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

METHODS

The records of 350 patients with complaints of lower urinary tract symptoms suggestive of benign prostatic hyperplasia were reviewed. Baseline parameters were international prostate symptom score, quality of life score, postvoid residual urine volume, prostate-specific antigen, and data obtained from uroflowmetry and transrectal ultrasonography. Urodynamic studies were carried out to determine bladder outlet obstruction. Receiver operator characteristic curves were generated to compare the accuracy of the different parameters, and the area under the curve of each parameter was calculated.

RESULTS

Bladder outlet obstruction index positively correlated with intravesical prostatic protrusion, total prostate volume, transition zone volume, transition zone index, resistive index and prostate-specific antigen. Further, resistive index was only a significant independent variable with intravesical prostatic protrusion. Intravesical prostatic protrusion had the highest area under the curve of 0.790 among all variables, and its cut-off value was 10 mm. The positive predictive value of intravesical prostatic protrusion was 76.2%. In addition, the positive predictive value of the combined parameters intravesical prostatic protrusion and resistive index increased to 83.8%.

CONCLUSIONS

Intravesical prostatic protrusion and resistive index are useful parameters for predicting bladder outlet obstruction in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia. In clinical practice, the combination of intravesical prostatic protrusion and resistive index on ultrasound can be diagnostic of bladder outlet obstruction.

Clinical Significance of the Resistive Index of Prostatic Blood Flow According to Prostate Size in Benign Prostatic Hyperplasia

Purpose:

The authors evaluated the relationships between the clinical factors and resistive indexes (RIs) of prostate and urethral blood flows by using power Doppler transrectal ultrasonography (PDUS) in men with benign prostatic hyperplasia (BPH).

Methods:

The data of 110 patients with BPH and lower urinary tract symptoms (LUTS) treated between January 2015 and July 2015 were prospectively collected. PDUS was used to identify the capsular and urethral arteries of the prostate in order to measure RIs. International Prostate Symptom Score (IPSS), maximal flow rate (Qmax), total prostate volume (TPV), transition zone volume (TZV), transition zone index (=TZV/TPV), presence of intravesical prostatic protrusion (IPP), and the RIs of capsular and urethral arteries were evaluated for all of the patients by one urologist.

Results:

The 110 patients were categorized according to IPSS (mild symptoms, 0–7; moderate symptoms, 8–19; and severe symptoms, 20–35), Qmax (<10 and ≥10 mL/sec), TPV (<30 and ≥30 mL), and presence or absence of IPP. No significant relationship was found between the mean RI of any artery and IPSS or Qmax. The mean RIs of the urethral artery, and left and right capsular arteries were significantly dependent on prostate size and the presence of IPP.

Conclusions:

RI obtained by using PDUS correlated with the presence of IPP and prostate size. The RI of prostate blood flow can be used as a noninvasive diagnostic tool for BPH with LUTS.

Tadalafil for lower urinary tract symptoms secondary to benign prostatic hyperplasia: a review of clinical data in Asian men and an update on the mechanism of action

Tadalafil, a phosphodiesterase type 5 (PDE5) inhibitor, is approved worldwide for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH-LUTS). The purpose of this narrative review is to summarize the clinical data on tadalafil 5 mg once-daily, primarily focusing on Asian men with BPH-LUTS, and to update the current understanding of the mechanism of action underlying PDE5 inhibition. Findings from studies have demonstrated that PDE5 is highly expressed in the lower urinary tract and supporting vasculature, and that PDE5 inhibition potentially decreases smooth muscle cell proliferation in the prostate, relaxes smooth muscle in the prostate, bladder neck and supporting vasculature, increases blood perfusion to the lower urinary tract, and modulates bladder afferent nerve activity. A total of 11 larger, 12-week, double-blind, randomized, placebo-controlled studies of tadalafil, including four Asian studies, have been conducted globally, enrolling >3000 men with BPH-LUTS. In addition, two long-term (42- and 52-week) studies enrolled 394 Japanese and 428 North American men, respectively, with BPH-LUTS. Overall, tadalafil 5 mg once-daily resulted in significant improvements in the change from baseline to endpoint in total International Prostate Symptom Scores (IPSS), IPSS storage and voiding subscores, and IPSS quality of life index compared with placebo. Tadalafil was well tolerated and had a favorable safety profile. These findings support tadalafil 5 mg once-daily for treating men, including Asian men, with BPH-LUTS.

Establishment and value assessment of efficacy prediction model about transurethral prostatectomy

OBJECTIVES

To establish and to evaluate discriminant models to predict the outcomes of transurethral prostatectomy.

METHODS

Clinical data of patients treated with transurethral prostatectomy between January and December 2013 were collected, including medical history, symptoms, biochemical tests, ultrasonography and urodynamics. Surgical efficacy was evaluated at 6-month follow up. Predictive models were constructed by logistic regression. Receiver operating characteristic curve and diagnostic tests were used to test the accuracy of models before the predictive value between models was compared.

RESULTS

A total of 182 patients were included, with 73.6% having an effective outcome. History of recurrent urinary tract infection (OR 1.33), score of storage phase (OR 2.58), maximum flow rate (OR 2.11) and detrusor overactivity (OR 3.13) were found to be risk factors. International Prostate Symptom Score (OR 0.13), transitional zone index (OR 0.58), resistive index of prostatic artery (OR 0.46), bladder wall thickness (OR 0.78), ultrasonic estimation of bladder weight (OR 0.28), bladder outlet obstruction index (OR 0.20) and bladder contractility index (OR 0.83) were found to be protective factors. The areas under the curve of models using factors from ultrasonography and urodynamics were 0.792 and 0.829 respectively, with no significant difference being found between them (P = 0.348).

CONCLUSIONS

Surgical efficacy of transurethral prostatectomy is positively correlated to severe voiding phase symptoms, outlet obstruction and better detrusor contractility, and negative correlated with urinary infection, severe storage phase symptoms and excessive detrusor contractibility. Ultrasonography might replace urodynamics in selecting patients for whom transurethral prostatectomy is more likely to be beneficial.

Are blood vessels a target to treat lower urinary tract dysfunction?

Bladder dysfunction is common in the general population (Stewart et al. 2010) and even more so among patients seeing a physician for any reason (Goepel et al. 2002). It often manifests as lower urinary tract symptoms (LUTS), a term originally coined to describe voiding and storage symptoms in men with benign prostatic hyperplasia (BPH) but now more universally used to describe any type of voiding and storage symptoms in both sexes. Studies into possible causes of urinary bladder dysfunction have long focused on detrusor smooth muscle cells (Turner and Brading 1999). More recently, it became clear that several other types of cells and organs contribute to regulating detrusor smooth muscle function. These include the urothelium (Andersson and McCloskey 2014; Michel 2015), afferent nerves (Michel and Igawa 2015; Yoshimura et al. 2014b), and the central and autonomic nervous systems (Fowler and Griffiths 2010; Yoshimura et al. 2014a). Alterations in any of these may at least partly be responsible for detrusor dysfunction and, accordingly, be potential targets for the treatment of bladder dysfunction. As highlighted by an article in this issue of Naunyn-Schmiedeberg's Archives of Pharmacology (Bayrak et al. 2015), there is an additional suspect, the bladder vasculature. This article will discuss the currently available experimental and clinical evidence for a role of the vasculature in causing bladder dysfunction, and how existing and emerging treatments may modulate bladder function by acting on blood vessels. Due to a similarity in concept, data on prostate perfusion will also be discussed to some extent.

Association between prostatic resistive index and cardiovascular risk factors in patients with benign prostatic hyperplasia

We evaluated the relationship between prostatic resistive index (RI) and cardiovascular system (CVS) risk factors in patients with benign prostatic hyperplasia. The study included 120 patients who were attending our outpatient clinic with lower urinary tract symptoms related to benign prostatic hyperplasia. The clinical, laboratory, anthropometric data, and CVS risk factors (hypertension, diabetes mellitus, metabolic syndrome, history of CVS events, and smoking) of the patients were evaluated regarding the association between prostate RI level by regression analyses. The prostatic RI levels of the patients were measured using power Doppler imaging. In univariate regression analysis, there were statistically significant relationships between prostatic RI levels and the patients' age, International Prostate Symptom Score, hip circumference, fasting blood glucose, prostate specific antigen, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total prostate volume, uroflowmetric maximal flow rate, and all investigated CVS risk factors (p < 0.05). The prostatic RI levels were found to be associated with fasting blood glucose and total prostate volume, and also with CVS risk factors including only metabolic syndrome and cigarette smoking in the multivariate regression analysis. Our results showed that prostatic RI level is significantly related to metabolic syndrome and smoking among the investigated CVS risk factors.

Resistive index of prostatic capsular arteries as a predictor of prostate cancer in patients undergoing initial prostate biopsy

To evaluate the value of resistive index (RI) of prostatic capsular arteries in diagnosis and evaluation of prostate cancer (PCa) in Chinese patients undergoing initial prostate biopsy. A total of 532 consecutive patients undergoing prostate biopsy were enrolled in this study. RI was measured on the largest transverse section of prostate for each individual. The predictive value of RI was evaluated using multivariate logistic regression and receiver operating characteristic (ROC) curve analyses. PCa was identified in 217 (40.79%) patients. RI was 0.69 ± 0.08 and 0.8 ± 0.08 for patients without and with PCa (p < 0.01). On logistic regression RI was significantly associated with PCa (p < 0.01). Using ROC analysis RI outperformed tPSA in prediction of PCa in all patients [area under ROC curve (AUC) = 0.83, 0.78, respectively]. With the cutoff value of 0.73, RI discriminated PCa from non-PCa patients with 81.9% sensitivity, 75.9% specificity and 77.63% diagnostic accuracy. Furthermore, The AUC for RI in the discrimination of PCa from non-PCa patients in a subset with PSA of 4 to 10 ng/ml, high grade from non-high grade PCa patients and advanced from localized PCa patients was 0.70, 0.77 and 0.80, higher than other parameters (p < 0.05). RI is proved a practicable parameter in identifying patients at risk for PCa and predicting the grade and stage of PCa before initial prostate biopsy. The value of RI should be further explored in the future.

Effects of medical therapy or surgery on prostatic and bladder resistive indices in patients with benign prostatic hyperplasia

INTRODUCTION

The effects of medical therapy or surgery on bladder and prostatic resistive indices (RIs) in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH) were evaluated in the present study.

PATIENTS AND METHODS

A total of 124 consecutive LUTS/BPH patients who were candidates for medical therapy (alfuzosin 10 mg once daily, n=66) or surgery (transurethral prostatectomy (TUR-P), n=58) were prospectively included. Baseline assessment of patients was performed with the International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax), and prostatic and bladder RIs measured using power Doppler imaging (PDI). All patients were re-evaluated 3 months after treatment measuring the same parameters.

RESULTS

Following medical therapy, mean IPSS (17.2±5.1 vs. 8.3±5.3, p=0.0001), postvoiding residual (PVR) urine (80.0±80.5 vs. 40.3±38.6, p=0.0001), and prostatic RI (0.73±0.1 vs. 0.70±0.1, p=0.0001) were decreased, Qmax (13.7±4.2 vs. 16.9±5.9, p=0.0001) was increased, and bladder RI remained unchanged (0.70±0.1 vs. 0.70±0.1, p=0.68). Mean IPSS (25.3±5.6 vs. 6.0±4.5, p=0.0001), PVR urine volume (134.5±115.5 vs. 35.7±25.9, p=0.0001), and prostatic (0.78±0.1 vs. 0.67±0.04, p=0.0001) and bladder RIs (0.72±0.1 vs. 0.64±0.04, p=0.005) were decreased, and Qmax (8.0±4.5 vs. 17.2±8.2, p=0.0001) was increased after TUR-P.

CONCLUSIONS

Our results demonstrated that TUR-P decreased both prostatic and bladder RIs, while α-blocker therapy did not change bladder RI in the early posttreatment period in LUTS/BPH patients.

Office evaluation of male patients with lower urinary tract symptoms

Lower urinary tract symptoms due to benign prostatic hyperplasia (LUTS/BPH) are one of the most common urologic disorders in men. Accurate history-taking and focused physical examination allows us to diagnose the majority of cases. A better understanding of risk factors helps us tailor our treatment and predict outcomes more accurately. Population studies are crucial in our understanding of LUTS/BPH natural history. Temporary prostatic urethral stents that are used for the management of urinary retention may also be used for evaluation of patients with detrusor hypo-contractility. The use of ultrasound to measure intravesical prostatic protrusion (IPP) and the Doppler study for prostate capsular artery resistive index are promising. Near-infrared spectroscopy (NIRS) examines the tissue oxygenation that may be affected by bladder outlet obstruction. The mathematical algorithm needs some fine-tuning, and its reproducibility is debatable. Serum and urinary biomarkers may help us to diagnose the disorder, and more effectively monitor patients' response to therapy. Among all, IPP is clinically more applicable at this time.