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D T Ubbink

Publications and source records attributed to D T Ubbink.

At least 37 records · Page 2Linked to original sources
PubMed2000

Optimisation of the non-invasive assessment of critical limb ischaemia requiring invasive treatment.

OBJECTIVE: to assess the optimal cut-off values of toe blood pressure (TBP) and transcutaneous oxygen pressure (TcpO(2)) in the supine and sitting positions, in order to accurately detect the presence of severe leg ischaemia requiring invasive treatment. METHODS: in 49 consecutive patients (65 legs) with severe ischaemia according to clinical symptoms of Fontaine III or IV and a lowered ankle blood pressure, TBP and TcpO(2)were measured in the supine and sitting positions. Treatment within 6 weeks after the diagnosis was classified as either conservative or invasive (revascularisation or amputation). RESULTS: of the 65 legs, 38 (58%) required invasive treatment. The mean ankle pressure for this group was 70 mmHg. The optimal cut-off value for TBP was 38 mmHg and for TcpO(2)35 mmHg. A TBP of </=30 mmHg and a TcpO(2)</=25 mmHg while supine, showed likelihood ratios (LR) of 7.0 and 3.3, respectively, and when combined an LR of 12.4. Measurements in the sitting position did not enhance diagnostic power. CONCLUSIONS: the need for invasive therapy in patients with severe leg ischaemia might be predicted by measuring TBP and TcpO(2), using the above-mentioned cut-off values.

Aged↗
PubMed2000

The usefulness of a laser Doppler in the measurement of toe blood pressures.

OBJECTIVE: The purpose of this study was to evaluate the clinical value and reproducibility of laser Doppler (LD) versus photoplethysmography (PPG) in the measurement of the systolic toe blood pressure. METHODS: Toe blood pressure was measured in 60 patients in different stages of peripheral vascular disease with simultaneous digital sampling of PPG and two LD signals, each with a different filter setting (3 second [LD(3)] and 0.03 second [LD(0.03)]), and cuff pressure. These measurements were repeated after 1 week. The signals were analyzed with previous results ignored. The agreement of the PPG and LD pressures and reproducibility after 1 week were assessed by calculating the intraclass correlation coefficient (ICC). The agreement variation across the range of pressure values was visually explored by means of difference plots. RESULTS: In 19 legs with a very low pressure only LD could adequately measure the pressure, whereas PPG did not. The ICCs between PPG and LD(3) and LD(0.03) were 0.95 or more. The ICCs of the 1-week reproducibility of the PPG, LD(3), and LD(0.03) pressures were 0.92, 0.88, and 0.86, respectively. The variation was equally distributed across the range of pressures in all three methods. CONCLUSION: LD is a reliable alternative to PPG to measure toe blood pressures. Furthermore, LD is able to measure low pressures, which is relevant in the assessment of the presence of critical ischemia.

Aged↗
PubMed2000

Collateral variations in circle of willis in atherosclerotic population assessed by means of transcranial color-coded duplex ultrasonography.

BACKGROUND AND PURPOSE: Transcranial color-coded duplex ultrasonography combined with common carotid artery (CCA) compression can be used to assess the collateral function of the circle of Willis. The aim of this study was to assess the unknown fraction of hemodynamic functional anterior and posterior communicating arteries (AcoA and PcoA, respectively) in an atherosclerotic population with no cerebrovascular symptoms. METHODS: In 76 patients with a mean age of 61 (35 to 89) years, the blood flow velocity changes in the precommunicating parts (A1 and P1, respectively) of the anterior and posterior cerebral arteries were measured during CCA compression. The AcoA was defined as functional if blood flow was reversed in the ipsilateral A1 and enhanced in the contralateral A1 during CCA compression. The PcoA was defined as functional if the flow velocity in the P1 was enhanced >20% during ipsilateral CCA compression. RESULTS: It was possible to assess cross flow through the anterior part of the circle of Willis in 95% of the subjects. Failure of this collateral pathway was caused by a hypofunctional AcoA in 4% and a hypofunctional A1 in 1% of the subjects. Anomalies in the posterior part of the circle of Willis hampering collateral flow from the basilar to the internal carotid artery were found in 45% of the hemispheres. Thirty-eight percent of PcoAs were hypofunctional, and 7% of the posterior cerebral arteries had a persistent fetal anatomy. CONCLUSIONS: We found that in subjects with no cerebrovascular symptoms, the anterior collateral pathway of the circle of Willis was nearly always functional. In contrast, the posterior collateral pathway was nonfunctional in almost half of the total number of hemispheres. Comparing these basic data with data from patients with cerebral ischemic disease might further help to elucidate the importance of the collateral capacity of the circle of Willis.

Adult↗
PubMed1999

Microcirculatory perfusion of the canine esophagus before and after blind longitudinal dissection and thoracoscopic distal transsection.

In the treatment of distal esophageal pathology, surgical mobilization and exteriorization of the thoracic esophagus can be necessary. This may threaten its vascularization. We investigated the effect of longitudinal dissection and distal transsection on the microcirculatory perfusion of the canine esophagus. Esophageal perfusion and muscular oxygenation were investigated in 11 dogs using laser Doppler fluxmetry and oxygen pressure measurements before and up to 2 weeks after longitudinal dissection with and without distal thoracoscopic transsection. Histological examination was performed at the end of the follow-up period. Distal esophageal perfusion was higher than proximal. Longitudinal dissection caused an insignificant reduction, whereas additional transsection significantly lowered esophageal perfusion, which was restored only partially during follow-up. After transsection distal muscular oxygen pressure was also significantly lower than proximal. Histologically, no significant ischemic cell damage was observed. Laser Doppler perfusion measurement is a feasible technique to measure (changes in) microcirculatory circulation of the esophageal wall. This may be useful in clinical settings to monitor the viability of the esophagus after surgical interventions. Distal transsection substantially reduces esophageal perfusion without apparent short-term histological damage.

Animals↗
PubMed1999

Red and green laser Doppler compared with capillary microscopy to assess skin microcirculation in the feet of healthy subjects.

Skin microvasculature consists of nutritive capillaries and subpapillary arteriolar and venular plexus connected by arteriolovenular anastomoses. Capillary perfusion is of paramount importance for skin viability. Recently a new combined laser Doppler instrument has become available, featuring a combination of near-infrared (RL; 780 nm) and green (GL; 543 nm) laser light sources. Theoretically, the red laser will penetrate deeper, whereas the green laser will read fairly superficially. This may enable differentiation between the more superficial, i.e., capillary, and the deeper skin layers. To test this hypothesis, the combined laser Doppler technique was compared with nail fold capillary microscopy in the feet of 10 healthy subjects. Seven males and 3 females with a median age of 26 (range 20-42) years and without arterial pathology were investigated. The laser Doppler (Periflux 4001, Perimed) was equipped with a special dual probe conducting both GL and RL. The probe was attached to the pulp of the big toe (with many AV-shunts) and to the nail fold, at the site where capillary microscopy was performed too. Laser Doppler and capillary perfusion was assessed at rest and during postocclusive reactive hyperemia. These measurements were performed both in the sitting and the supine positions to test the postural vasoconstriction response. Median resting and hyperemic skin perfusion with GL were lower (P < 0.01) than with the RL in both areas and positions, except for the resting value in the sitting position on the dorsum of the toe. Plantar perfusion was found significantly higher than dorsal perfusion only with the RL in the supine position (P < 0.01). GL and RL on the plantar, but not the dorsal, side showed a significantly decreased perfusion upon dependency (P < 0.05), both at rest and during hyperemia. In contrast, resting and peak capillary velocity did show a decrease on dependency (P < 0.05). Although the green laser measures a lower perfusion than does the red laser, which is likely to be derived from more superficial skin layers, it does not show a reactivity similar to that measured with capillary microscopy. Thus, it is questionable whether the green laser exclusively measures capillary perfusion.

Adult↗
PubMed1999

Microcirculatory investigations to determine the effect of spinal cord stimulation for critical leg ischemia: the Dutch multicenter randomized controlled trial.

PURPOSE: Patients with non-reconstructable critical limb ischemia generally undergo medical treatment only to prevent or postpone amputation. There is some evidence that spinal cord stimulation (SCS) stimulates ischemic wound healing. Thus, this could benefit limb survival through improved skin perfusion. We investigated the effect of SCS versus conservative treatment on skin microcirculation in relation to treatment outcome in patients with non-reconstructable critical limb ischemia. METHODS: Standard medical treatment plus SCS was compared with only standard medical treatment in a multicenter randomized controlled trial comprised of 120 patients with surgically non-reconstructable chronic rest pain or ulceration. We investigated skin microcirculation by means of capillary microscopy, laser Doppler perfusion, and transcutaneous oxygen measurements in the foot. The microcirculatory status just before treatment was classified in three categories (poor, intermediate, and good) and was related to limb survival after a minimum follow-up period of 18 months. RESULTS: Clinical parameters, peripheral blood pressures, and limb survival rates showed no significant differences between the SCS and standard groups during the follow-up period. In both treatment groups, amputation frequency after 18 months was high in patients with an initially poor microcirculatory skin perfusion (SCS 80% vs standard treatment 71%; NS) and low in those with a good skin perfusion (29% vs 11 %, respectively; NS). In patients with an intermediate skin microcirculation amputation, frequency was twice as low in patients additionally treated with SCS as in the standard treatment group (48% vs 24%; P =.08). In these patients, microcirculatory reactive hyperemia during the follow-up period reduced in the standard group but not in the SCS group (P <.01). CONCLUSION: Selection on the basis of the initial microcirculatory skin perfusion identifies patients in whom SCS can improve local skin perfusion and limb survival.

Adult↗
PubMed1999

Prediction of imminent amputation in patients with non-reconstructible leg ischemia by means of microcirculatory investigations.

PURPOSE: We investigated the usefulness of skin microcirculatory investigations to predict imminent major amputation in patients with non-reconstructible critical limb ischemia. METHODS: One hundred eleven patients with non-reconstructible chronic rest pain or small ulcers and an ankle blood pressure of 50 mm Hg or less or an ankle-to-brachial pressure index of 0.35 or less were included. Nailfold capillary microscopy (CM; big toe, sitting), transcutaneous oxygen pressure (TcpO2; forefoot, supine; 44 degrees C), and laser Doppler perfusion measurements (LD; pulp of big toe, supine) were performed at rest and during reactive hyperemia. Patients were classified according to their skin microcirculatory status just before the start of the treatment in three groups: those with a "good," "intermediate," or "poor" microcirculation, according to a combination of predefined cutoff values (Poor: capillary density less than 20/mm2, absent reactive hyperemia in CM and LD, TcpO2 less than 10 mm Hg; good: capillary density of 20/mm2 or more, present reactive hyperemia in CM and LD, TcpO 2 of 30 mm Hg or more). Subsequently, patients received maximum conservative therapy from the surgeon, who was unaware of the microcirculatory results. After a follow-up period of as long as 36 months, limb survival and disposing factors were analyzed and compared with the initial microcirculatory status. RESULTS: Cox regression analysis showed a significant prognostic value of the microcirculatory classification (hazard ratio = 0.28, P <.0001), but not of the Fontaine stage, ankle blood pressure, or the presence of diabetes mellitus for the occurrence of an amputation. Positive and negative predictive values were 73% and 67%, respectively. The cumulative limb survival at 6 and 12 months was 42% and 17% in the poor microcirculatory group, 80% and 63% in the intermediate microcirculatory group, and 88% and 88% in the good microcirculatory group ( P <.0001, log-rank). CONCLUSION: Microcirculatory screening and classification is useful in detecting non-reconstructible critical ischemia that requires amputation, which is not detectable by means of the clinical stage or blood pressure parameters. Most of the poor patient group will require amputation. In the intermediate and good groups, nonsurgical treatment appears sufficient for limb salvage.

Aged↗
PubMed1999

Effects of venous pressure and posture on skin capillary perfusion.

BACKGROUND: Various vasoconstriction mechanisms after a change in posture are involved in controlling skin blood flow and capillary transmural pressure to maintain adequate transcapillary exchange. The role of venous orthostatic pressure in the regulation of capillary nutritive perfusion, however, is less clear. DESIGN: We investigated capillary perfusion in 30 healthy subjects using intravital capillary microscopy of the big toenail-fold. Measurements were made in the supine and the sitting positions before and after incremental elevation of venous resistance, and thus the pre- to post-capillary pressure difference, by inflating a cuff around the ankle. RESULTS: On dependency, median capillary density rose (P < 0.0001), whereas red blood cell perfusion decreased (P < 0.0001). Cuff inflation of 30-60 mmHg in the supine position induced similar phenomena. Repeatedly, the same capillaries were found to be recruited after an increase in transmural pressure. CONCLUSIONS: We conclude that post-capillary pressure appears to be an important factor in the regulation of capillary perfusion, because an increase in venous resistance mimics the effects of dependency. The findings in this study support the theory of 'minimum perfusion pressure' for each capillary to be perfused with erythrocytes.

Adult↗
PubMed1999

Influence of the collateral function of the circle of Willis on hemispherical perfusion during carotid occlusion as assessed by transcranial colour-coded duplex ultrasonography.

OBJECTIVES: to investigate the collateral potential of the circle of Willis with transcranial colour-coded duplex ultrasonography and common carotid artery (CCA) compression. MATERIALS AND METHODS: in 46 atherosclerotic patients without cerebrovascular disease, the functional patency of the collaterals of the circle of Willis, the anterior and posterior communicating arteries, was assessed. The Peak Systolic Velocity (PSV) decrease in the middle cerebral artery (MCA) during CCA compression between complete and incomplete circles was compared. RESULTS: in 10 (22%) patients a complete and in 36 (78%) patients an incomplete circle of Willis was found, mainly due to non-functioning posterior communicating arteries. In hemispheres with collateral supply through both the anterior and the posterior communicating artery, the median PSV decrease in the MCA during CCA compression was 43%. When the posterior, anterior or both communicating arteries (1 hemisphere) were missing the PSV decrease was 58% (p =0.003), 70% (p =0.001) and 75%, respectively. CONCLUSIONS: collateral flow from the basilar to the carotid territory is often hampered by non-functioning posterior communicating arteries. A non-functioning anterior communicating artery is rare. A complete collateral circulation provides better perfusion of the MCA during carotid occlusion as compared with collateral supply through only the anterior or the posterior communicating artery in the case of an incomplete circle of Willis.

Adult↗
PubMed1999

Success rate of transcranial color-coded duplex ultrasonography in visualizing the basal cerebral arteries in vascular patients over 60 years of age.

BACKGROUND AND PURPOSE: Clinically important atherosclerotic cerebrovascular disease is mainly found in patients aged >60 years. Transcranial color-coded duplex ultrasonography (TCCD) is a relatively new technique for investigating the basal cerebral arteries; however, it is often hampered by impenetrable ultrasound windows. The aim of this study was to ascertain the as yet unknown success rate of TCCD regarding visualization of the basal cerebral arteries in patients >60 years, to provide reference data, and to compare any possible male/female differences. METHODS: In 112 atherosclerotic white patients >60 years of age, the anterior, middle, and posterior cerebral arteries and the vertebral and basilar arteries were insonated. RESULTS: In men, 99% of the temporal and 94% of the suboccipital windows could be penetrated by ultrasound compared with 77% and 95%, respectively, in women. The male versus female vessel detection rates were 91% versus 58% for the anterior cerebral artery, 97% versus 73% for the middle cerebral artery, 97% versus 68% for the posterior cerebral artery, 94% versus 93% for the vertebral artery, and 91% versus 79% for the basilar artery. In 77% of men but only 33% of women could all vascular segments be investigated. All intracranial arteries were insonated at a deeper level in men. The women showed significantly higher blood flow velocities than the men. CONCLUSIONS: In elderly white men the vessel detection rate is >90%. In women there is a much lower detection rate, due to impenetrable temporal windows. Visualization of all major intracranial arteries is possible in only one third of female patients >60 years of age.

Aged↗
PubMed1999

Influence of repetitive finger puncturing on skin perfusion and capillary blood analysis in patients with diabetes mellitus.

BACKGROUND: Frequent puncturing of fingers to check blood glucose in patients with type 1 diabetes might alter skin perfusion and, hence, influence the representativeness of the blood sample. We investigated the influence of repetitive puncturing on skin microcirculatory perfusion using laser Doppler fluxmetry and on the preanalytical phase of capillary blood analysis for small molecules (glucose) and large particles (cholesterol). METHODS: In 49 patients with long-standing (mean, 21 years) type 1 diabetes, with a mean puncture frequency of three times daily for a mean duration of 13 years, laser Doppler skin perfusion was measured in a finger at a frequently punctured site and compared with a similar site of another finger of the same hand, which was never punctured. In the supine position with the hand level with the heart, resting flux (RF), peak flux (PF), and the microcirculatory reserve capacity (MRC; PF - RF) were assessed. Subsequently, blood samples for capillary whole blood glucose and cholesterol analyses were taken from the same sites. RESULTS: No significant differences were found between the puncture and control sites in mean RF (2.3 vs 2.0 V; P = 0.14, paired-samples t-test), PF (3.3 vs 3.1 V; P = 0.24), MRC (1.0 vs 1.0 V; P = 0.65), glucose (10.2 vs 10.2 mmol/L; P = 0.69), or cholesterol (5.1 vs 5.2 mmol/L; P = 0.26). Power calculation for a RF of 2.0 V and the SD and n of this study indicate a power (beta) of 80% to detect a 25% change in RF at P <0.05. CONCLUSIONS: Repetitive finger puncturing in diabetics appears not to injure local skin microcirculatory perfusion nor to influence results of capillary blood analysis for glucose and cholesterol.

Adult↗
PubMed1997

The value of non-invasive techniques for the assessment of critical limb ischaemia.

OBJECTIVE: The European Consensus Document (ECD) defines critical ischaemia (CI) according to clinical (Fontaine) and blood pressure parameters. However, clinical symptoms may be non-specific and CI may exist without severely reduced blood pressures. This study prospectively investigated the additive value of transcutaneous oxygen tension (pO2) and toe blood pressure measurements to assess the presence of CI. METHODS: Forty-nine patients with 65 legs clinically classified as Fontaine stages III (n = 23) and IV (n = 26) were studied. Ankle and toe systolic blood pressure and pO2 were measured to assess the presence of CI (cut-off values were 50, 30 and 30 mmHg, respectively). The surgeon was blinded for the toe pressure and pO2 results. The treatment received within 1 month after presentation was recorded as being either conservative or invasive (vascular surgery or PTA). RESULTS: An ankle pressure of < or = 50 mmHg classified only 17% of the legs as having CI. By adding toe pressure and pO2, significantly more legs (63%; p < 0.0001) were classified as CI, of which 68% received invasive therapy. Forty-nine percent of the legs with an ankle pressure > 50 mmHg were treated invasively, whereas only 32% of the legs classified as not having CI by means of toe pressure and pO2 underwent invasive therapy. If the need for invasive treatment is used as the "gold standard" for the presence of CI, 54% of the legs would accurately be classified on the basis of the ankle blood pressure. The combination of toe pressure and pO2 would have yielded 71% and the ECD criteria 72% and accurately classified legs. The odds ratio for invasive therapy given a pO2 or toe pressure above the cut-off value was 14. CONCLUSION: Ankle blood pressure measurements have limited diagnostic value. Adding toe and/or oxygen pressures enhances the detection of CI requiring invasive therapy.

Aged↗
PubMed1997

Diabetes mellitus is not a contra-indication for peripheral vascular intervention in patients with leg ischemia.

BACKGROUND: The effect of diabetes mellitus on the patency of peripheral vascular interventions was investigated in patients with arterial insufficiency of the leg in a retrospective follow-up study performed between 1993 and 1995. METHODS: In 65 patients without and 36 with diabetes 124 vascular reconstructions were performed because of rest pain and/or ulceration. RESULTS: In diabetic patients ulcers were found more frequently and more distal bypasses were performed. No significant differences were observed between diabetics and non-diabetics as to bypass patency, number of re-interventions and amputations. Smoking and age were significant factors influencing bypass patency. CONCLUSION: Diabetes mellitus in patients with critical leg ischaemia appears to be no reason to refrain from vascular surgery.

Aged↗
PubMed1995

Can transcutaneous oximetry detect nutritive perfusion disturbances in patients with lower limb ischemia?

Transcutaneous oximetry (TcpO2) performed at 37 and 44 degrees on the dorsum of the foot and capillary microscopy of the nailfold of the big toe were applied to 85 patients with various (including asymptomatic) stages of lower limb ischemia to appreciate the relationship between (disturbances in) capillary perfusion and skin oxygen tension. In mildly diseased patients, capillary perfusion as measured by direct observation, was preserved. In critically ischemic patients in the supine position, red blood cell-perfused capillary density was reduced. Nutritive perfusion was severely reduced and showed an absent reactive hyperemia after a 1-min arterial occlusion. Also, postural vasoconstrictive activity was reduced. TcpO2 measured at 37 degrees was very low already in mildly diseased patients, illustrating the poor oxygen diffusion toward the skin. At 44 degrees, TcpO2 was severely reduced in critically ischemic patients. Reactive hyperemic response and postural vasoconstriction were suppressed, due to local heating of the skin. Measurement of the TcpO2 has limitations in the assessment of nutritive perfusion, as opposed to capillary microscopy, since it is an indirect measure of skin perfusion, not necessarily derived from capillaries only. The obligatory local skin heating impairs physiological studies as to hyperemic reserve capacity or postural constriction mechanisms. Thus, transcutaneous oximetry is a poor method of characterizing pathophysiological mechanisms occurring in skin nutritive microcirculation. However, capillary microscopy and transcutaneous oximetry can give additive information as to the severity of peripheral ischemia. Peak red blood cell velocity during reactive hyperemia using capillary microscopy and the resting TcpO2 at 44 degrees, both measured in the supine position, appeared to be valuable microcirculatory parameters in detecting critical limb ischemia.

Adult↗
PubMed1995

Capillary microscopy is a diagnostic aid in patients with acral ischemia.

The diagnosis of peripheral ischemic diseases is a challenge to the vascular specialist, since discrimination of the different entities on clinical grounds is not always clear. Capillary microscopy is a noninvasive diagnostic technique that can visualize in particular the morphology and perfusion of the digital capillaries. The authors investigated all 522 patients who were referred to the vascular laboratory over a six-year period, in an attempt to obtain more certainty about the diagnosis of their acral ischemic complaints. Patients with clinically manifest Raynaud's phenomenon and control subjects were compared to obtain differentiation criteria. Thus, capillary microscopy scored a sensitivity of 67%, a specificity of 84%, and an accuracy of 81% to detect Raynaud's phenomenon. A disturbed capillary morphology was virtually pathognomonic in Raynaud's disease secondary to systemic disorders (specificity 100%); the accuracy was but 74%. In 69% of the patients with clinically atypical acral ischemia, capillary microscopy yielded a diagnosis. Digital blood pressure measurements, however, appeared of no use in the diagnosis of Raynaud's phenomenon. Hence, capillary microscopy appears to be a useful aid in the diagnosis of acral ischemic syndromes.

Adolescent↗