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Biomedical subjects

D S Sumner

Publications and source records attributed to D S Sumner.

At least 73 records · Page 4Linked to original sources
PubMed1985

Noninvasive assessment of stroke risk in asymptomatic and nonhemispheric patients with suspected carotid disease. Five-year follow-up of 294 unoperated and 81 operated patients.

Based on the assumption that greater than or equal to 50% stenosis of the internal carotid artery increases stroke risk, noninvasive tests are being used to screen patients for prophylactic carotid endarterectomy. To assess the validity of this concept, 104 asymptomatic and 190 nonhemispheric patients referred for cerebrovascular tests were reviewed after 5 years. Carotid stenosis greater than or equal to 50% predicted a 15% stroke incidence at 2 years compared to a 3% incidence with 1-49% stenosis (p less than or equal to 0.05). Five-year cumulative stroke incidence was 21% with greater than 50% stenosis, 14% with 1-49% stenosis (NS), and 9% with 0% stenosis (p less than 0.05). Stenosis greater than or equal to 50% predicted increased cardiac mortality (p less than 0.025). Hypertensive patients, greater than 70 years, with greater than or equal to 50% stenosis had a 37% incidence of stroke; normotensive patients, less than 70 years, with or without stenosis, had few strokes. In patients with greater than or equal to 50% disease, surgery reduced the 5-year stroke rate from 21 to 8% (p less than 0.05), mitigated the effects of age and hypertension, and improved survival. Noninvasive test results must be considered in conjunction with age and hypertension in predicting stroke risk.

Actuarial Analysis↗
PubMed1985

Digital subtraction angiography: intravenous and intra-arterial techniques.

As experience with digital subtraction angiography (DSA) increases, both its advantages and disadvantages have become more evident. Although the intravenous approach (IV-DSA) is safer and less expensive than conventional arteriography, images are frequently suboptimal. Good-quality IV-DSAs quite accurately detect hemodynamically significant lesions (sensitivity 92% and specificity 92%) but may overlook minor stenoses and wall irregularities (negative predictive value 69%). When fine detail is not required, IV-DSA may serve as the definitive radiographic examination. The intra-arterial approach (IA-DSA), which provides better images, uses less contrast medium, decreases the need for selective catheterization, and permits visualization of vessels in areas of sluggish flow, is being used more extensively. Careful consideration of the complementary roles of DSA, conventional arteriography, and noninvasive testing is necessary to provide accurate diagnostic information at the least hazard and expense to the patient.

Angiography↗
PubMed1985

Are strokes predictable with noninvasive methods: a five-year follow-up of 303 unoperated patients.

To determine the correlation between the degree of internal carotid arterial stenosis demonstrated by noninvasive tests and the risk of subsequent stroke, 303 consecutive patients who underwent cerebrovascular evaluation with the Hokanson ultrasonic arteriograph were reviewed retrospectively. Ninety percent of the patients were followed up for 5 years or until the time of death. Stroke occurred in 41 (13.5%) patients. There was a significant correlation (p = 0.04) between the incidence of stroke and severity of disease: greater than or equal to 50% stenosis (19%), 0% to 49% stenosis (11%), and no stenosis (10%). Stroke as a presenting complaint carried the highest risk of subsequent neurologic defect (24%), but the risk in patients without symptoms was appreciable (15%). Life-table analysis indicated that the incidence of stroke was low (less than 3%) in the asymptomatic and nonhemispheric group during the first 2 years after evaluation when the degree of stenosis was less than 50%. Thereafter, the stroke rate increased. Half the deaths were due to myocardial infarction; the risk of death from cardiac causes was doubled in patients with greater than 50% stenosis. It is concluded that the demonstration of hemodynamically significant stenosis does select a group of patients at increased risk for subsequent stroke and myocardial infarction, but lesser degrees of stenosis do not exclude future neurologic events.

Actuarial Analysis↗
PubMed1984

Influence of the contralateral carotid artery on neurologic complications following carotid endarterectomy.

To examine the effect of contralateral carotid artery stenosis on postoperative events, a retrospective review was made of 451 patients undergoing 510 carotid endarterectomies during a 6-year period. Three degrees of contralateral carotid stenosis were identified radiologically: 0% to 49%, 50% to 99%, and totally occluded. Each group was further separated into two categories according to preoperative symptoms. "Low risk" included asymptomatic lesions, transient ischemic attacks, and nonhemispheric symptoms; "high risk" described poststroke patients and urgent operations. The results show the incidence of stroke or death was not increased in patients with severely stenosed or occluded contralateral vessels in either low- or high-risk patients (p = 0.741 and p = 0.561, respectively). Patients in the high-risk category, however, had a significantly higher risk of postoperative complications than patients in the low-risk category (p less than 0.001). The study reaffirms that preoperative indications have a major influence on surgical outcome and suggests that the status of the contralateral artery has little bearing on postoperative events.

Adult↗
PubMed1983

Digital subtraction angiography for evaluation of extracranial carotid occlusive disease: comparison with conventional arteriography.

Conventional arteriography (CA) was performed for 78 of 688 patients who underwent digital subtraction angiography (DSA) for suspected extracranial carotid arterial disease. Prospective readings by radiologists and retrospective readings by the authors were used to compare the results of the two studies in 142 internal carotid arteries (ICAs). DSA findings were uninterpretable for 10% (prospective) and 16% (retrospective) of the ICAs. For detecting the presence or absence of any disease evident on CA, the sensitivity and specificity of DSA (prospective) were 86% and 88%, respectively. The accuracy for differentiating diameter stenosis greater than 50% from stenosis of lesser degree was 80% sensitivity and 94% specificity. Negative or uninterpretable DSA results occurred in 22% of ICAs with stenosis visible on CA, in 22% of 46 ICAs subjected to endarterectomy, and in 66% of ICAs with ulcerated plaques. DSA obviated CA for 34% of patients undergoing endarterectomy. Symptoms had little influence on the decision to obtain CA, but the degree of stenosis did--the greater the stenosis visible on DSA, the more likely that CA was performed. DSA is a good method for evaluating disease at the carotid bifurcation, but its limitations must be appreciated if it is to be employed rationally.

Angiography↗
PubMed1983

Computerized multiplanar imaging and lumen area plotting for noninvasive diagnosis of carotid artery disease.

Some of the errors associated with pulsed Doppler imaging of the carotid bifurcation relate to the fact that the vessels are usually viewed in only one plane. To reduce these projection errors, a computerized ultrasonic arteriograph (CUA) was developed, which simultaneously produces lateral and anteroposterior images of the carotid bifurcation together with a histogram that depicts the cross-sectional area of the lumen at 1 mm points along the vessel. The area measured from the histogram and that estimated from biplanar arteriograms agreed in 46/57 (81%) of the internal carotid arteries studied by both techniques. The area histogram was positive for 91% of the arteries with arteriographically visible disease and was 79% specific for eliminating the presence of disease. The combined CUA study (histogram plus images) had a sensitivity and specificity of 96% and 80% for detecting any disease, 96% and 92% for evaluating diameter stenoses of 20%, and 89% and 98% or evaluating stenoses of 40%. These preliminary results suggest that the CUA may enhance the accuracy of pulsed Doppler imaging.

Carotid Artery Diseases↗
PubMed1982

Intracranial pressure and cerebral arterial pulsatile flow measurement in neonatal intraventricular hemorrhage.

We examined the clinical significance of noninvasive intracranial pressure measurements and pulsatility indices in 74 infants with confirmed IC-IVh. The intracranial pressure measurements were obtained using the applanation principle, and the pulsatility indices were calculated from the Doppler flow velocity tracings of the anterior cerebral artery. Fifty-three infants (71.6%) who died had a significantly lower birth weight and gestational age than those who survived. Survival rate decreased significantly with increased intracranial pressure (P less than 0.0002) and increased pulsatility indices (P less than 0.0001). We found no significant relationship between outcome and the size of IC-IVH demonstrated by CT scan. Birth weight, intracranial pressure measurements, and cerebral arterial pulsatile flow changes appear to be major prognostic indicators in neonatal IC-IVH.

Birth Weight↗
PubMed1982

Are noninvasive tests sufficiently accurate to identify patients in need of carotid arteriography?

Noninvasive studies were performed on 1771 patients with suspected extracranial cerebrovascular disease. Of these, 328 underwent arteriography, providing 604 arteriograms for comparison with carotid phonoangiography (CPA), 516 for comparison with pulse-delay oculoplethysmography (OPG), and 571 for comparison with pulsed Doppler ultrasonic arteriograms (UAs). The UA was the most sensitive test, detecting 92% of the internal carotid stenoses of 60% or more and 72% of those between 20% and 59%. When the results of three tests were combined, the sensitivity was 80% and the specificity was 61% for any recognizable disease at the carotid bifurcation. Ninety percent of stenoses of 20% or more and 95% of stenoses of 40% or more were detected by the combination. The UA identified 86% to 93% of patients with operable disease, and combined studies identified 88% to 95%. Carotid endarterectomies were performed on 112 patients. The UA was positive in 91% to 96% of the patients undergoing surgery, and combined testing was positive in 96%. This study suggests that noninvasive tests are capable of identifying most patients in need of carotid endarterectomy.

Blindness↗
PubMed1980

Hemodynamic studies of digital and extremity replants and revascularizations.

Blood pressure, blood flow, skin temperature, pulse contour, and sympathetic nerve activity were investigated by noninvasive methods in 33 fingers, five arms, and one foot that had been replanted or revascularized 2 to 30 months previously. Results from the operated parts were contrasted with those from the same part on the contralateral normal extremity and with those obtained from normal controls. Mean blood pressure in operated fingers (97 +/- 18 mm Hg) was significantly lower than that in nonoperated (114 +/- 16 mm Hg) and control (115 +/- 17 mm Hg) fingers. Mean blood flow in operated fingers (16 +/- 100 ml/100 ml/min) was significantly less than that in nonoperated (23 +/- 11 ml/100 ml/min) and control (28 +/- 20 ml/100 ml/min) fingers. In 80% of the studies, blood pressure and blood flow were less on the operated side than on the nonoperated side; however, 75% of the blood pressure determinations and all of the blood flows fell within the 95% confidence limits of the control values. Skin temperatures were not decreased and sympathetic activity had returned in 91% of the fingers. It is concluded that the perfusion of tissues surviving replantation or revascularization usually is within normal limits but often is reduced when compared to that of normal tissues of the same individual.

Adolescent↗
PubMed1979

Noninvasive diagnosis of extracranial carotid arterial disease: a prospective evaluation of pulsed-Doppler imaging and oculoplethysmography.

Two hundred consecutive internal carotid arteries were examined with the Hokanson-pulsed Doppler ultrasonic arteriograph (UA) and the Kartchner-McCrae oculoplethysmograph (OPG). Roentgenographic studies were used to assess the relative accuracy of these two noninvasive tests. Diameter stenoses estimated from the UA and roentgenographic images agreed within +/- 20% in 81% of the studies. The UA detected 61% of all stenoses of 20% to 39% and 89% of all stenoses greater than 40%. A sensitivity of 86% and a specificity of 90% were achieved with the UA compared with a sensitivity of 64% and a specificity of 85% with the OPG. When the UA and OPG agreed (67% of the vessels), the sensitivity was 95% and the specificity was 94%. When they disagreed, the UA was the better test having a sensitivity of 81% compared with 21% with the OPG.

Angiography↗
PubMed1979

Reliability of Doppler ultrasound in the diagnosis of acute venous thrombosis both above and below the knee.

We have found the Doppler examination to be accurate in 92% of limbs with suspected iliofemoral thrombosis and in 86% of limbs with suspected calf vein thrombosis. Above the knee, the sensitivity was 94% and the specificity, 90%. Below the knee, the sensitivity was 91% and the specificity, 84%. In the hands of a skilled examiner, Doppler ultrasound is a reliable noninvasive technique for evaluating patients with suspected deep venous thrombosis and one on which therapy can safely be based.

Anticoagulants↗
PubMed1979

Noninvasive diagnosis of neonatal asphyxia and intraventricular hemorrhage by Doppler ultrasound.

The cerebrovascular hemodynamic alterations in asphyxia and intracerebral-intraventricular hemorrhage were determined by monitoring the pulsatile flow changes in the anterior cerebral arteries using Doppler ultrasound. The pulsatility index measurements, which were calculated from the recorded changes in Doppler frequency shifts, were obtained in four groups of newborn infants with the following diagnoses: Group I--normal term (n=21); Group II--asphyxia (n=12); Group III--IC-IVH (n=14); and Group IV--asymptomatic preterm (n=11). There was no significant difference between PI values of Groups I and IV. Compared to normal term infants, those diagnosed as having asphyxia had significantly lower PI measurements and those with IC-IVH had significantly higher PI values than the asymptomatic pretern infants. Serial Doppler studies were also performed in 22 preterm infants with respiratory distress. One-half of these infants subsequently developed IC-IVH. Prior to hemorrhage, their PI measurements were significantly lower than those who did not eventually have the complication. The low PI values in asphyxia and prior to the onset of IC-IVH indicate vasodilation and decreased resistance to blood flow. In IC-IVH, the high PI measurements denote the opposite. In infants with respiratory distress in the presence of significant vasodilation and lowered vascular resistance, CBF may increase to excessive levels, resulting in IC-IVH.

Asphyxia Neonatorum↗