Noninvasive urodynamics: a study of male voiding dysfunction.

A group of 26 patients was tested for isovolumetric pressure and optimal flow rate by means of the cuff-uroflow (CUF) technique. The same patients were also examined in the clinic, and a diagnosis was recorded. The two processes were performed independently in a statistically double-blind manner. Standard statistical comparisons were made, and it was shown that there exists substantial correlation between the results of clinical examination and the cuff-uroflow procedure. It was also shown that the CUF technique converged more rapidly to a correct diagnosis than standard clinical procedures. Surgical treatment and watchful waiting were examined and it was shown, as expected, that surgical treatment resulted in substantial improvement in most cases, but that watchful waiting generated no statistically significant change.

Noninvasive quantitative method for measuring isovolumetric bladder pressure and urethral resistance in the male: I. Experimental validation of the theory.

Noninvasive measurement of intravesical pressure, impulsive flow rate, and localized urethral resistance is achieved by clamping the penis immediately above the glans with a pneumatic cuff and then instructing the patient to initiate voiding. The cuff is then deflated slowly until urinary flow of at least 1 ml/s is detected and is then released rapidly to permit unimpeded flow. Cuff pressure, voided volume, and flow rate are recorded as functions of time. From the resulting tracings it is possible to determine the isovolumetric bladder pressure, the impulsive flow rate, and the flow pattern specific to the test. We studied 53 male patients demonstrating that data thus obtained are reproducible and that the cuff pressure at the initiation of voiding does measure the bladder pressure at this moment. We then modeled the lower urinary tract by an analog electrical circuit which facilitated the analysis of the urodynamic data. This analysis suggests that it is possible to separate the effects of bladder dysfunction from the effects of urethral resistance and to localize the resistance to the proximal or distal urethra without invasive testing.

Objective noninvasive evaluation of benign prostatic hypertrophy.

An objective noninvasive procedure has been developed to evaluate the urodynamics of benign prostatic hypertrophy. The test uses pneumatic occlusive cuffs similar to those used for blood pressure measurements and the electrical engineering concepts of open-circuit, short-circuit, and transient response measurements. The cuff is first inflated to measure pressure, then rapidly released, yielding the transient response and subsequent unimpeded flow. From the pressure and flowrate recordings as functions of time, objective evaluations of bladder strength and urethral obstruction are extracted.

Pressure and volume measurements from the eye for detecting possible arterial obstruction.

Detection and evaluation of functionally significant carotid occlusive disease are effectively achieved by noninvasive pressure and/or volume measurements from the eye. Ocular arterial blood pressure is measured by applying either direct compression or suction to evaluate intraocular pressure to the point of arterial collapse. Carotid blood flow is evaluated as it affects ocular volume waveforms, which result from the difference between pulsatile arterial flow and relatively constant venous flow. The relationship between noninvasive measurements from the eyes and carotid blood flow can be predicted using simple models of the cervical-cerebral circulatory system. Proper models verify clinically observed correlations between pressure and volume measurements from the eye and the underlying carotid occlusive disease. Electrical analog circuits provide a method for varying model parameters to simulate abnormalities, producing waveforms with good similarity to waveforms recorded from patients with known vascular or ophthalmic pathology. Further model refinements can be contributed by interested investigators. By using the improved models the strengths and weaknesses of current tests and techniques can then be better defined. Techniques that have been widely used for screening and evaluating potential stroke patients can thereby be modified to give improved functional analysis of these patients.

Carotid occlusive disease as a risk factor in major cardiovascular surgery.

Carotid occlusive disease in patients undergoing major cardiovascular surgery raises the question of the perioperative risk factor of stroke. We evaluated 234 cardiovascular patients preoperatively by oculoplethysmography (OPG) to detect hemodynamically severe carotid occlusive disease. The perioperative stroke risk without flow-reducing carotid occlusive disease was 1%, in contrast to a 17% incidence of stroke when OPG studies indicated internal carotid artery stenosis of more than 60%. Oculoplethysmography is a reliable indicator of hemodynamically severe carotid occlusive disease with an associated high risk of stroke that warrants prophylactic carotid endarterectomy before major cardiovascular surgery.

Guidelines for noninvasive evaluation of asymptomatic carotid bruits.

Basic recommendations for follow-up utilizing OPG/CPA results are as follows: Grade 1: Repeat studies in 12 months in the absence of specific focal TIAs or increase of bifurcation level bruit. Grade 2: Serial studies in 6 to 12 months in the absence of focal TIAs which provide their own indications for evaluation. If stability is established, 12-month interval testing is adequate. Grade 3: Serial studies in 3 to 6 months until a progression trend is established. Anticipation of major surgery with possible hypotension or severe blood loss is an indication for arteriography and possible endarterectomy. Grade 4: If repeat studies confirm grade 4 status, prophylactic carotid arteriography and endarterectomy should be seriously considered. If surgery is not employed, repeat OPG/CPA evaluation at 2 to 4 month intervals detects further progression toward total occlusion. Grade 5: Indications for arteriography in anticipation of surgery are tempered by the lower probability (30%) of a surgically correctable stenosis and the clinical status of the patient. In conclusion, we feel that OPG/CPA represents one valid means of noninvasively evaluating the presence and underlying hemodynamic significance of an asymptomatic bruit with sufficient reliability to justify angiography and prophylactic carotid endarterectomy on the basis of appropriate findings.

Oculoplethysmography and carotid phonoangiography for the noninvasive detection of extracranial carotid occlusive disease.

Clinical applications of imaging techniques and noninvasive physiological vascular evaluations provide useful assistance in the detection and management of stroke-prone patients by minimizing unnecessary carotid arteriography and surgery. Two such evaluation techniques are oculoplethysmography (OPG) and carotid phonoangiography (CPA). Developed, used, and proved highly reliable at the Tucson (Arizona) Medical Center, the techniques have been documented in 12,000 tests on approximately 8500 patients. OPG simultaneously records the bilateral ocular pulses concomitantly with external carotid pulses. Delays in timing of these pulses reflect reduction of flow in the internal and/or external carotid arteries, respectively. CPA consists of electronic stethoscopic auscultation, direct visualization, and photographic recording of carotid bruits or blood flow sounds.

Noninvasive evaluation and management of the "asymptomatic" carotid bruit.

Cervical bruits in patients who are asymptomatic or who have nonhemispheric neurological symptoms present a universal challenge. Of 4,000 patients evaluated noninvasively for carotid occlusive disease, 1,287 presented with "asymptomatic" bruits (697 had nonhemispheric neurological symptoms and 590 were clinically asymptomatic). Carotid phonoangiography (CPA), the visual analysis of carotid bruits, identifies bruits indicative of significant stenosis, documents progression, and differentiates bruits of carotid bifurcation and sub-bifurcation origin. Sub-bifurication bruits were diagnosed in 619, insignificant bifurcation bruits in 426, and significant carotid bruits in 242 patients by CPA. Oculoplethysmography (OPG) evaluates the hemodynamic significance of carotid bruits by comparative timing of simultaneously recorded ocular and ear lobe pulses. OPG detected 273 asymptomatic bruit patients with significant internal carotid flow reduction and indicated 5% of the bifurcation bruits were of external carotid origin. An accuracy of 89% in determining greater than 40% stenosis by OPG/CPA in 295 patients having arteriography increases to 97% when both OPG and CPA are positive. Six-month to 70-month clinical follow-up of the 1,287 patients documented 154 carotid endarterectomies and 38 strokes. Analysis of the strokes favors arteriography and operation only for those patients with appropriately positive or progressive OPG/CPA or with focal transient ischemic attacks (TIAs).

Oculoplethysmography: an adjunct to arteriography in the diagnosis of extracranial carotid occlusive disease.

A four and a half year study documents that oculoplethysmography, in conjunction with carotid phonoangiography, fulfills the criteria of an effective noninvasive adjunct to arteriography in the diagnosis of extracranial carotid occlusive disease. The risk and expense of unnecessary arteriographic studies can be reduced and accuracy of arteriographic technics and interpretations can be enhanced by routine application of oculoplethysmography.