Jarlis Wesche

Dynamics and dimensions of cardiac output changes in humans at the onset and at the end of moderate rhythmic exercise.

1. An improved Doppler ultrasound technique was used to measure stroke volume (SV) and cardiac output (CO) on a beat‐to‐beat basis in a group of supine humans before, during and after periods of standardized, rhythmic exercise, involving the quadriceps muscle groups on both sides. The development of CO on such bouts of exercise was compared to Doppler ultrasound records of the simultaneous femoral arterial flow (FF) response. 2. Records of CO at rest revealed spontaneous fluctuations around a mean level, with differences between the minimal and maximal values of the order of 1 l min‐1. The mean CO level at rest again varied considerably from one day to another and from test run to test run. 3. Upon start of exercise an immediate and rapid increase in heart rate (HR) and CO took place. The entire increase, the size of which varied appreciably from test run to test run, was completed within 10‐15 s. No or only minor changes were seen in the mean SV level during the exercise periods. 4. The time course of the increase in FF was indistinguishable from that of the increase in CO, which occurred without any detectable delay relative to the changes in FF. These closely parallel developments indicate a tight regulatory coupling between the two types of flow changes. 5. In the majority of tests the total and two‐sided increase in FF seen in the steady‐state situation in the last part of an exercise period was significantly larger than the recorded increase in CO. This discrepancy implies that some redistribution of flow from tissues other than the working muscles might take place, even at this moderate level of work. 6. Upon the end of exercise a striking but transient increase in CO occurred, resulting from an increase in SV concomitant with a maintained HR. In the course of five to eight post‐exercise cardiac cycles about 100 extra milliliters of blood were expelled from the heart. This cardiac outflow overshoot was found to occur during a post‐exercise fall in mean arterial blood pressure (MAP).

Three-dimensional ultrasound-based navigation combined with preoperative CT during abdominal interventions: a feasibility study.

AbstractPurpose: Three-dimensional (3D)nintraoperative ultrasound may be easier to interpret when used inncombination with less noisy preoperative image data such as CT. Thenpurpose of this study was to evaluate the use of preoperative imagendata in a 3D ultrasound-based navigation system specially designed fornminimally invasive abdominal surgery. A prototype system has beenntested in patients with aortic aneurysms undergoing clinical assessmentnbefore and after abdominal aortic stent-graft implantation. nMethods: All patients were first imaged by spiral CTnfollowed by 3D ultrasound scanning. The CT volume was registered to thenpatient using fiducial markers. This enabled us to comparencorresponding slices from 3D ultrasound and CT volumes. The accuracy ofnthe patient registration was evaluated both using the external fiducialnmarkers (artificial landmarks glued on the patient’s skin) and usingnintraoperative 3D ultrasound as a measure of the true positioning ofnanatomic landmarks inside the body. nResults: The meannregistration accuracy on the surface was found to be 7.1 mm, butnincreased to 13.0 mm for specific landmarks inside the body. CT andnultrasound gave supplementary information of surrounding structures andnposition of the patient’s anatomy. Fine-tuning the initial patientnregistration of the CT data with a multimodal CT to intraoperative 3Dnultrasound registration (e.g., mutual information), as well as ensuringnno movements between this registration and image guidance, may improventhe registration accuracy. nConclusion: Preoperative CTnin combination with 3D ultrasound might be helpful for guiding minimalninvasive abdominal interventions.

DOPPLER MEASUREMENTS OF CHANGES IN HUMAN MAMMARY AND UTERINE BLOOD FLOW DURING PREGNANCY AND LACTATION

A pulsed Doppler ultrasound velocity meter was used to measure blood velocities in the right uterine artery and a mammary branch of the right lateral thoracic artery in one subject throughout pregnancy and after parturition. The breast blood velocity was also followed throughout lactation. The velocities in the uterine artery increased 2.5‐fold from the 15th to the 38th week, when delivery occurred. An estimate of the total blood flow in the uterine artery, based on the total intensities in the Doppler spectrum, increased 5‐fold in the same period. This corresponds to the increase in volume flow obtained with invasive methods. Velocities in the breast artery increased 2.5‐fold from the 12th to the 25th week of pregnancy and then stayed at the same level throughout lactation; after weaning, they rapidly declined.

Electrophysiological Evidence of Reinnervation of the Transplanted Human Heart

Beat-by-beat heart rate (HR) changes during exercise were studied in two young and fit heart-transplanted humans at different time intervals following transplantation. Upon the start of the exercise, a slow gradual increase in HR was seen during the early experiments after the transplantation, whereas an immediate rapid increase in HR was observed during the later experiments. From standard ECGs obtained 32 months after transplantation, two P waves at somewhat different rates could be identified in both subjects, probably arising from donor and recipient sinoatrial nodes, respectively. The two P wave rate changes during and following exercise were very similar. We conclude that these changes in the HR pattern and ECG must be due to reinnervation of the donor hearts, most likely by parasympathetic cardiac fibers.

Editor's Choice – The National Norwegian Carotid Study: Time from Symptom Onset to Surgery is too Long, Resulting in Additional Neurological Events

OBJECTIVE/BACKGROUNDnThe objective was to observe for 1 year all patients in Norway operated on for symptomatic carotid stenosis with respect to (i) the time from the index event to surgery and neurological events during this time; (ii) the level in the healthcare system causing delay of surgical treatment; and (iii) the possible relationship between peri-operative use of platelet inhibitors and neurological events while awaiting surgery.nnnMETHODSnThis was a prospective national multicentre study of a consecutive series of symptomatic patients. Patients were eligible for inclusion when referred for surgery. An index event was defined as the neurological event prompting contact with the healthcare system. All 15 departments in Norway performing carotid endarterectomy (CEA) participated.nnnRESULTSnThree hundred and seventy one patients were eligible for inclusion between 1 April 2014 and 31 March 2015, and 368 patients (99.2%) were included. Fifty-four percent of the patients contacted their general practitioner on the day of the index event. Primary healthcare referred 84.2% of the patients to hospital on the same day as examined. In hospital median time from admission to referral for vascular surgery was 3 days. Median time between referral to the operating unit and actual CEA was 5 days. Overall, 61.7% of the patients were operated on within 2 weeks of the index event. Twelve patients (3.3%) suffered a new neurological event while awaiting surgery. The percentage of patients on dual antiplatelet therapy was lower (25.0%) in this group than among the other patients (62.6%) (pxa0=xa0.008). The combined 30xa0day mortality and stroke rate was 3.8%.nnnCONCLUSIONnThis national study with almost complete inclusion and follow-up shows that the delays occur mainly at patient level and in hospital. The delay is associated with new neurological events. Dual antiplatelet therapy is associated with reduced risk of having a new neurological event before surgery.

Does venous insufficiency impair the exercise-induced rise in arterial leg blood flow?

Objectives It has been shown that the leg muscle pump increases the immediate rise in arterial leg blood flow during upright exercise in healthy subjects. The present study is the first to investigate the muscle pump effect in exercise hyperaemia in patients with venous insufficiency, who should be lacking an optimally functioning muscle pump. Methods Any muscle pump effect is more pronounced in an upright position because of gravitation. The exercise-induced rise in femoral artery flow (FF) (ultrasound Doppler) was thus compared in the supine and 30° head-up tilted position in 10 patients. Results Neither the transient nor the steady-state rise in FF showed any difference between positions. This is in contrast to the previous findings in healthy subjects, where the transient rise in FF was larger in the tilted position. Conclusion The muscle pump effect in exercise hyperaemia seems to be reduced or lacking in these patients.

Does the great saphenous vein stripping improve arterial leg blood flow during exercise

OBJECTIVESnIt has been shown that the leg muscle pump increases arterial leg blood flow during upright exercise in healthy subjects, and that this effect is reduced in patients with incompetence of the great saphenous vein (GSV). In this study, patients with GSV reflux causing varicose veins were investigated after GSV stripping, to see whether the muscle pump effect on arterial leg blood flow is improved.nnnDESIGNnProspective case study.nnnMETHODSnNine patients with GSV incompetence resulting in symptomatic varicose veins, but without peripheral artery disease were included in this study. Patients exercised in the supine and 30° head up tilted positions by rhythmically pressing down a pedal with one foot. Blood flow was measured in the femoral artery using Doppler ultrasound. The Exercise-induced rise in femoral artery blood flow was compared in the supine and 30° head up tilted positions. Patients were investigated both before and after undergoing saphenofemoral ligation and GSV stripping as a treatment for their varicose veins. The arterial blood flow response to exercise was compared between the pre and postoperative observations.nnnRESULTSnPrior to GSV stripping the immediate rise in femoral flow was 0.25 l min(-1) above rest in both supine and tilted positions. After GSV stripping however, the rise in flow was 30% larger in the tilted position than in the supine position (0.26 vs. 0.20 l min(-1), P < 0.05).nnnCONCLUSIONSnGSV stripping modestly improves arterial leg blood flow at the onset of exercise in patients with GSV insufficiency, because of an improved effect of the leg muscle pump.

Validation of the Vascular quality of life questionnaire – 6 for clinical use in patients with lower limb peripheral arterial disease

BackgroundThe VascuQoL-6 (VQ-6) health-related quality of life questionnaire, a short version of the disease-specific VascuQoL-25, was developed for clinical practice and use in vascular registries. The study purpose was to evaluate the validity and reliability of VQ-6.MethodsVQ-6 was translated to Norwegian with linguistic validation and face value evaluation, and consecutive patients with intermittent claudication (IC) or critical limb ischemia (CLI) were included. All patients completed VQ-6 and Short Form-36 (SF-36), and were evaluated with ankle-brachial index (ABI) measurement pre- and post-exercise, a constant load treadmill test and clinical consultation at baseline and after 4xa0weeks. Correlation analysis, change statistics and receiver operator characteristics (ROC) curves were used to evaluate reliability, validity and responsiveness to change.ResultsOne hundred seventy-one patients withxa0peripheral arterial disease (PAD) were included, 70 (41%) female. 147 (86%) of the patients suffered from IC. The reliability of VQ-6 was good, Cronbachs-α 0.82. The ability of VQ-6 to differentiate between IC and CLI was good, area under the curve (AUC) 0.754. There was good correlation between SF-36 physical domains and component scores and VQ-6 score (rxa0=xa00.55–0.62) and excellent responsiveness to change after treatment, standard response mean (SRM) 1.12. The clinical anchors of ABI at rest, treadmill walking performance and Fontaine class improvement were less responsive to change than VQ-6, SF-36 and the vascular surgeon’s evaluation.ConclusionsVQ-6 is reliable and valid, and can be used to evaluate PAD treatment in clinical practice and in vascular registries. Further research is necessary to determine the clinically important change over time.Trial registrationISRCTN14846962 (retrospectively registered).

Additional functional outcomes after endovascular treatment for intermittent claudication

Background Endovascular treatment (EVT) for intermittent claudication (IC) is performed in selected patients where conservative treatment and training fail. Treatment outcomes reported in vascular registries (survival, limb-survival, and re-intervention rate) are inadequate for low-risk patients with IC. Additional measurements of blood flow reduction and functional impairment clarify the indication for treatment and facilitate outcome evaluation. Purpose To analyze the additional outcome information on peripheral arterial pressures and walking capacity obtained from a local registry of EVT. Material and Methods Patients with IC treated with endovascular technique (angioplasty or stent) were prospectively entered into a local registry in addition to the national registry (NORKAR), with information on arterial pressures (ankle brachial index [ABI]) and treadmill performance (maximum walking distance [MWD]). Results A total of 242 consecutive patients (41% women; median age, 70 years) receiving the first treatment between July 2010 and December 2012 were included, 61% with aorto-iliac lesions. After 3 months, mean ABI increased from 0.62 (0.59–0.64) to 0.85 (0.83–0.87). The median MWD increased from 160u2009m to 410u2009m. Sixty-two percent reached the test maximum of 10u2009min. The improvement in ABI and MWD persisted after 1 year. When preoperative ABI was moderately reduced (0.5–0.9), ABI was normal in 61% after 3 months and in 55% after 1 year. When preoperative ABI was low (<0.5), ABI was normal in 43% both after 3 months and 1 year. Conclusion ABI and walking capacity were important outcome variables and improved after EVT. ABI improvement was better for patients with moderately reduced preoperative ABI than with low ABI.

Acute Axillary/Subclavian Vein Thrombosis

A 34-year-old male motor mechanic was admitted with a 3-day history of severe swelling of the right arm. He had been undertaking physical activity, including weightlifting, training for about 1.5 h four times a week. There was no history of trauma. The patient was feeling discomfort but no severe pain in the arm. The superficial veins were distended. The colour of the hand and forearm was slightly cyanotic. The pulses in the radial and ulnar arteries were palpable. No bruits could be heard along the brachial, supraclavicular or axillary arteries. The rest of the examination was unremarkable. The patient was not using any medication.