Treatment of severe intermittent claudication with PGE1--a short-term vs a long-term infusion plan--a 20 week, European randomized trial--analysis of efficacy and costs

Intravenous Prostaglandin E1 Infusion for Acute Central Retinal Artery Occlusion

BACKGROUND AND OBJECTIVE

To evaluate the efficacy of systemic prostaglandin E1 (PGE1) infusion within the first 24 hours of acute central retinal artery occlusion (CRAO).

PATIENTS AND METHODS

Best corrected visual acuity (BCVA) was analyzed in a case series of six eyes from six patients (mean age: 69.33 years) with acute CRAO who were treated with twice-daily intravenous infusion of 40 μg PGE1. Therapy continued until the patient no longer experienced visual acuity improvements for 24 hours.

RESULTS

Average time to presentation was 8.33 hours (range: 2 to 12 hours). The logMAR BCVA at presentation was 2.73. BCVA at the final visit 1 month after initial presentation was 1.48 (P = .025). All patients experienced vision improvement. No systemic adverse events were experienced.

CONCLUSION

Intravenous PGE1 infusion resulted in significant visual improvement in patients presenting with acute CRAO and is well tolerated with few adverse effects. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:S5-S8.].

Active and Passive Optical Imaging Modality for Unobtrusive Cardiorespiratory Monitoring and Facial Expression Assessment

Because of their obvious advantages, active and passive optoelectronic sensor concepts are being investigated by biomedical research groups worldwide, particularly their camera-based variants. Such methods work noninvasively and contactless, and they provide spatially resolved parameter detection. We present 2 techniques: the active photoplethysmography imaging (PPGI) method for detecting dermal blood perfusion dynamics and the passive infrared thermography imaging (IRTI) method for detecting skin temperature distribution. PPGI is an enhancement of classical pulse oximetry. Approved algorithms from pulse oximetry for the detection of heart rate, heart rate variability, blood pressure-dependent pulse wave velocity, pulse waveform-related stress/pain indicators, respiration rate, respiratory variability, and vasomotional activity can easily be adapted to PPGI. Although the IRTI method primarily records temperature distribution of the observed object, information on respiration rate and respiratory variability can also be derived by analyzing temperature change over time, for example, in the nasal region, or through respiratory movement. Combined with current research areas and novel biomedical engineering applications (eg, telemedicine, tele-emergency, and telemedical diagnostics), PPGI and IRTI may offer new data for diagnostic purposes, including assessment of peripheral arterial and venous oxygen saturation (as well as their differences). Moreover, facial expressions and stress and/or pain-related variables can be derived, for example, during anesthesia, in the recovery room/intensive care unit and during daily activities. The main advantages of both monitoring methods are unobtrusive data acquisition and the possibility to assess vital variables for different body regions. These methods supplement each other to enable long-term monitoring of physiological effects and of effects with special local characteristics. They also offer diagnostic advantages for intensive care patients and for high-risk patients in a homecare/outdoor setting. Selected applications have been validated at our laboratory using optical PPGI and IRTI techniques in a stand-alone or hybrid configuration. Additional research and validation is required before these preliminary results can be introduced for clinical applications.

Effects of Shock Waves on Microcirculation, Perfusion, and Pain Management in Critical Limb Ischemia

Shock waves (SW) are used to control pain in different clinical conditions (eg, painful knee, elbow, and shoulder, etc). The effects of SWs may be due to cellular “stunning” (particularly nervous components). It may also be the consequence of unknown metabolic actions on tissues, which may include changes in cellular permeability, the liberation of proteins and mediators locally acting on pain and nerve endings. The aim of this study was to evaluate the reduction in pain and the improvement in microcirculation induced by SW treatment in a 2-week study in patients with chronic limb ischemia (CLI). Of the 32 patients with CLI, 30 (20 with rest pain only, 10 with necrosis) completed the study. The treatment was well tolerated. Foot radiographs performed before and after treatment indicate no bone damage after treatment. Foot (tibial arteries) blood pressure was unchanged after 2 weeks. The increase in laser Doppler flux was significant (p<0.05) after treatment. The ORACLE score at 2 weeks was decreased (p<0.05). The same trend was observed with the analogue scale line for pain (p<0.05). Partial pressure of oxygen (PO2) increased (p<0.05) and partial pressure of carbon dioxide (PCO2) decreased (p<0.05). In all patients an increase in pain-free walking distance was observed (the distance increased on average 2.4 times). Flux improvement was still present after 1 month. The outcome at 3 months in these patients indicates that the improvement (concerning the survival of the limbs) was persistent. In conclusion SWs treatment in CLI produced changes both on the microcirculation and pain. These results are very interesting, confirming previous observations, and opening new treatment options in CLI. The skin flow improvement did not relate to an increase in pressure.

Investigating the Generalizability of Economic Evaluations Conducted in Italy: A Critical Review

OBJECTIVES

To assess the methodological quality of Italian health economic evaluations and their generalizability or transferability to different settings.

METHODS

A literature search was performed on the PubMed search engine to identify trial-based, nonexperimental prospective studies or model-based full economic evaluations carried out in Italy from 1995 to 2013. The studies were randomly assigned to four reviewers who applied a detailed checklist to assess the generalizability and quality of reporting. The review process followed a three-step blinded procedure. The reviewers who carried out the data extraction were blind as to the name of the author(s) of each study. Second, after the first review, articles were reassigned through a second blind randomization to a second reviewer. Finally, any disagreement between the first two reviewers was solved by a senior researcher.

RESULTS

One hundred fifty-one economic evaluations eventually met the inclusion criteria. Over time, we observed an increasing transparency in methods and a greater generalizability of results, along with a wider and more representative sample in trials and a larger adoption of transition-Markov models. However, often context-specific economic evaluations are carried out and not enough effort is made to ensure the transferability of their results to other contexts. In recent studies, cost-effectiveness analyses and the use of incremental cost-effectiveness ratio were preferred.

CONCLUSIONS

Despite a quite positive temporal trend, generalizability of results still appears as an unsolved question, even if some indication of improvement within Italian studies has been observed.

Non-arteritic Posterior Ischaemic Optic Neuropathy Treated with Intravenous Prostaglandin E1 and Oral Corticosteroids

Intravenous prostaglandin E1 and oral corticosteroids were used to treat the ischaemic phase of a non-arteritic posterior ischaemic optic neuropathy with immediate visual improvement. Non-arteritic posterior ischaemic optic neuropathy is a disorder of reduced blood flow to the retrobulbar optic nerve, usually of acute onset. It has been suggested that high-dose steroid therapy given soon after the onset of visual loss can result in significant visual improvement. This treatment, however, is not universally successful. The addition of a potent vasodilator to the corticosteroids could help restore ocular blood flow and improve visual acuity. This paper presents the use of prostaglandin E1 (PGE1), a powerful vasodilator of the microcirculation, to treat non-arteritic posterior ischaemic optic neuropathy. In this case report a 68-year-old white male with hereditary haemochromatosis was seen 8 hours after sudden loss of visual acuity in his left eye (OS) to 4/10. The diagnosis of non-arteritic posterior ischaemic optic neuropathy was made and he was immediately given oral corticosteroids. Intravenous PGE1 was given the next morning, 24 hours after the sudden loss of vision, once ischaemia of the optic nerve was confirmed by colour Doppler imaging. The visual acuity in the OS improved from 4/10 to 11/10 within 1 day. A visual field (VF) post treatment showed a peripheral scotoma without a central scotoma. At 12 months post treatment the vision OS remained 11/10. No complications due to the use of PGE1 were seen. The authors conclude that PGE1 should be considered in addition to steroids in cases of NA-PION to immediately restore blood flow to the optic nerve and improve visual acuity.

Photoplethysmography and its application in clinical physiological measurement

Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. It is often used non-invasively to make measurements at the skin surface. The PPG waveform comprises a pulsatile ('AC') physiological waveform attributed to cardiac synchronous changes in the blood volume with each heart beat, and is superimposed on a slowly varying ('DC') baseline with various lower frequency components attributed to respiration, sympathetic nervous system activity and thermoregulation. Although the origins of the components of the PPG signal are not fully understood, it is generally accepted that they can provide valuable information about the cardiovascular system. There has been a resurgence of interest in the technique in recent years, driven by the demand for low cost, simple and portable technology for the primary care and community based clinical settings, the wide availability of low cost and small semiconductor components, and the advancement of computer-based pulse wave analysis techniques. The PPG technology has been used in a wide range of commercially available medical devices for measuring oxygen saturation, blood pressure and cardiac output, assessing autonomic function and also detecting peripheral vascular disease. The introductory sections of the topical review describe the basic principle of operation and interaction of light with tissue, early and recent history of PPG, instrumentation, measurement protocol, and pulse wave analysis. The review then focuses on the applications of PPG in clinical physiological measurements, including clinical physiological monitoring, vascular assessment and autonomic function.

Photoplethysmography detection of lower limb peripheral arterial occlusive disease: a comparison of pulse timing, amplitude and shape characteristics

The assessment and diagnosis of lower limb peripheral arterial occlusive disease (PAOD) is important since it can lead progressively to disabling claudication, ischaemic rest pain and gangrene. Historically, the first assessment has been palpation of the peripheral pulse since it can become damped, delayed and diminished with disease. In this study we investigated the clinical value of objective photoplethysmography (PPG) pulse measurements collected simultaneously from the right and left great toes to diagnose disease in the lower limbs. In total, 63 healthy subjects and 44 patients with suspected lower limb disease were studied. Pulse wave analysis techniques extracted timing, amplitude and shape characteristics for both toes and for right-to-left toe differences. Normative ranges of pulse characteristics were then calculated for the healthy subject group. The relative diagnostic values of the different pulse features for detecting lower limb arterial disease were determined, referenced to the established ankle-brachial pressure index (ABPI) measurement. The ranges of pulse characteristics and degree of bilateral similarity in healthy subjects were established, and the degrees of pulse delay, amplitude reduction, and damping and bilateral asymmetry were quantified for different grades of disease. When pulse timing, amplitude and shape features were ranked in order of diagnostic performance, the shape index (SI) gave substantial agreement with ABPI (>90% accuracy, kappa 0.75). SI also detected higher grade disease, for legs with an ABPI less than 0.5, with a sensitivity of 100%. The simple-to-calculate timing differences between pulse peaks produced a diagnostic accuracy of 88% for all grades of arterial disease (kappa 0.70), and 93% for higher grade disease (kappa 0.77). These contrasted with the limited discriminatory value of PPG pulse amplitude. The low-cost and simplicity of this optical-based technology could offer significant benefits to healthcare, such as in primary care where non-invasive, accurate and simple-to-use (de-skilled) diagnostic techniques are desirable.

Acute branch retinal arterial embolism successfully treated with intravenous prostaglandin E1--case reports

The purpose of this paper is to report the use of intravenous prostaglandin E1, a potent vasodilator, to rapidly restore blood flow and vision in a patient with an acute branch retinal arterial occlusion. An 82-year-old woman with an acute decrease in the visual acuity of her left eye due to an acute superior temporal branch retinal arterial embolus was treated with 140 microg of intravenous prostaglandin E1. The medicine was repeated the following day. At the onset of the branch arterial occlusion her vision in the left eye was 20/50, the embolus could be seen in the superior temporal branch, and a white retinal edema extended down into the macula. At her first eye examination 4 days after treatment, her visual acuity had returned to 20/20, the retinal embolus was still present, but the white macular edema had disappeared. Intravenous prostaglandin E1 is a safe, potent vasodilator for the peripheral vascular system. If used immediately to treat acute branch arterial retinal occlusions, it can restore good vision. The authors report the first case of the use of intravenous prostaglandin E1 to treat a spontaneous acute branch retinal arterial embolus.

Ocular and orbital blood flow velocity in patients with peripheral vascular disease and diabetes treated with intravenous prostaglandin E1

The purpose of this study was to evaluate the effect of intravenous prostaglandin E1 (PGE1) on the flow velocity of the ophthalmic artery and the central retinal artery in patients with peripheral vascular disease manifested by intermittent claudication. The flow velocity of these vessels is frequently decreased in vascular patients. Since these patients were already being treated with PGE1 for their intermittent claudication, the authors wanted to evaluate the effect on the flow velocity of the ocular vessels as well. A randomized 21-week study of two groups of vascular patients was performed. The first group had intermittent claudication. The second group had intermittent claudication and were also diabetics. Both groups were treated with intravenous PGE1 for their intermittent claudication. Using the color Doppler, the flow velocities of the ophthalmic artery and central retinal artery were measured before and after the intravenous treatment. Before treatment, the flow velocity of the ophthalmic artery and the central retinal artery was decreased when compared to that in the normals. After treatment, there was a significant increase in the systolic and diastolic phases of the flow velocity in both arteries. The systolic flow velocity increased by as much as 40%, and the diastolic flow velocity increased by as much as 80%. The flow velocities of the ophthalmic artery and the central retinal artery are frequently decreased in certain ocular diseases, and this decreased flow may contribute to the ocular pathology. If intravenous PGE1 is able to increase the flow velocity of these vessels in patients with peripheral vascular disease, it is possible that it is also able to increase the flow velocity of these vessels in patients with ocular disease as well. Intravenous PGE1 may prove to be a useful adjunct therapy in eyes when ischemia is part of the pathology.

The influence of intraarterial prostaglandin E(1) on vascular hydraulic impedance and infrainguinal graft patency

OBJECTIVES

To evaluate the influence of intraoperative arterial prostaglandin E(1)(alprostadil) infusion on hydraulic impedance in relation to graft patency.

METHODS

Hydraulic impedance was measured in 115 infrainguinal bypasses by means of the extracorporeal-bypass-flow method (EBF). Fifty-eight femoro-popliteal and 57 femoro-crural polytetrafluoroethylene (PTFE) grafts were included. 10 microg of alprostadil were administered into a temporary bypass and the haemodynamic changes were recorded. The reactions of input (Z(x)) and characteristic (Z(0)) impedances as well as phase relations were derived and related to graft outcome after three years.

RESULTS

Significant changes after administration of prostaglandin were observed for overall pressure (74 vs. 84 mmHg, p<0.01), flow rate (194 vs 160 ml/min, p<0.01), input impedance (0.55 vs. 0.75 PRU, p<0.01) and the phase angle of the first harmonic (-18 degrees vs -26 degrees, p<0.01). An increase of at least one degree of the first harmonic phase angle following alprostadil injection in the crural bypass group was associated with a significant better graft prognosis of crural (p<0.01) but not popliteal grafts. Primary and secondary patency rates after three years for crural grafts with an increase of at least one degree were 62% and 63% (n=45) and for non-responders 18% and 0% (n=12, p(prim)<0.01, p(sec)<0.001). All crural bypasses with poor prostaglandin reaction occluded within 9 months (n=12) after the operation.

CONCLUSIONS

The EBF method allows a combined assessment of peripheral resistance and impedance parameters. The response of the first harmonic phase angle provides important predictive information regarding femoro-crural grafts.

PGE(1) treatment of severe intermittent claudication (short-term versus long-term, associated with exercise)--efficacy and costs in a 20-week, randomized trial

The efficacy, safety, and cost of prostaglandin E1 (PGE1) in the treatment of severe intermittent claudication was studied comparing a long-term treatment protocol (LTP) with a short-term treatment protocol (STP) in a randomized 20-week study. The study included 980 patients (883 completed the study) with an average total walking distance of 85.5 +/-10 m (range 22-119). Phase 1 was a 2-week run-in phase (no treatment) for both protocols. In LTP, phase 2 was the main treatment phase. In the LTP, treatment was performed with 2-hour infusions (60 microg PGE1, 5 days each week for 4 weeks. In phase 3 (4-week interval period) PGE1 was administered twice a week (same dosage). In phase 4 (monitoring lasting 3 months, from week 9 to 20) no drugs were used. In STP phase 2 treatment was performed in 2 days by a 2-hour infusion (first day: morning 20 microg, afternoon 40 microg; second day morning and afternoon 60 microg). The reduced dosage was used only at the first cycle (week 0) to evaluate tolerability or side effects. Full dosage (60 microg bid) was used for all other cycles. The same cycle was repeated at the beginning of weeks 4, 8, and 12. The observation period was between weeks 12 and 20. A treadmill test was performed at inclusion, at the beginning of each phase, and at the end of 20th week. A similar progressive physical training plan (based on walking) and a reduction in risk factors levels plan was used in both groups. Intention-to-treat analysis indicated an increase in walking distance, which improved at 4 weeks and at 20 weeks in the STP more than in the LTP group. At 4 weeks the variation (increase) in pain-free walking (PFWD) was 167.8% (of the initial value) in the LTP group and 185% in the STP group (p<0.05). At 4 weeks the variation (increase) in total walking distance (TWD) was 227.6% of the initial value in the LTP group and 289% in the STP group (p<0.05). At 20 weeks the increase in PFWD was 496% of the initial value in the LTP group vs 643% in the STP group (147% difference; p<0.02). The increase in TWD was 368% in the LTP group and 529% in the STP group (161% difference; p<0.02). In both groups there was a significant increase in PFWD and TWD at 4 and 20 weeks, but results obtained with STP are better considering both walking distances. No serious drug-related side effects were observed. Local, mild adverse reactions were seen in 6.3% of the treated subjects in the LTP and 3% in the STP. Average cost of LTP was 6,664 Euro; for STP the average costs was approximately 1,820 E. The cost to achieve an improvement in walking distance of 1 m was 45.8 E with the LTP and 8.5 E with the STP (18% of the LTP cost; p<0.02). For an average 100% increase in walking distance the LTP cost was 1,989 E vs. 421 E with STP (p<0.02). Between-group analysis favors STP considering walking distance and costs. Results indicate good efficacy and tolerability of PGE, treatment. With STP less time is spent in infusion and more in the exercise program. STP reduces costs, speeds rehabilitation, and may be easily used in a larger number of nonspecialized units.

Effects of shock waves on the microcirculation in critical limb ischemia (CLI) (8-week study)

Shock waves (SWs) are used to control and decrease pain in several clinical conditions (e.g., painful elbow and shoulder, etc). This clinical effect may be due to cellular stunning of the tissues (particularly nervous components) in the area treated with SW. It may also be the consequence of unknown metabolic actions on tissues, which may include changes in cellular permeability and the liberation of proteins and mediators locally acting on pain and nerve endings. The aim of this study was to evaluate the reduction in pain and the microcirculation improvement induced by SWs treatment in an 8-week study in patients with chronic limb ischemia (CLI). Patients with CLI (15 with rest pain only and 15 with rest pain and limited distal necrosis) were included. The treatment was based on a 30-minute SWs session, three times weekly for 2 weeks. Clinical and microcirculatory evaluation were performed with laser Doppler Po2 and Pco2 measurements. Pain was measured with an analogue scale line. A Minilith SL1 (Storz Medical, Switzerland) litotriptor was used. The parabolic reflector is coupled to the skin with a silicon water cushion. Focal pressure was adjusted between 6 and 70 Mpa in eight steps. The energy flux density was variable from 0.03 to 0.5 mJ/mm2. Focal diameter and distance were defined (depth of target within the patient's foot of about 70 mm). The coded intensity used in this study was between 6 and 8 and the application time was 20 min (at four impulses per second). Twenty-eight of the 30 patients with CLI (15 with rest pain only and 13 with necrosis) completed the study. The treatment was well tolerated. Blood pressure was unchanged after 8 weeks while the increase in laser Doppler flux was significant (p<0.05) (at all measurements after treatment). The ORACLE score at 1 and 8 weeks was decreased (p<0.05). The same trend was observed with the analogue scale line for pain (p<0.05). PO2 increased (p<0.05) and Pco2 decreased (p<0.05). Tibial pressure did not change. All patients observed an increase in their subjective pain-free walking distance. The improvement was still present after 8 weeks. In a separate subset of 37 patients (mean age 60+/-9 years; males) with CLI, a SWs dose-finding evaluation was performed. Flux changes were measured at the dorsum of the foot. Three treatment plans were used: (a) 20-minute SW treatment only once; (b) 20-minute SWs treatment every 2 days for 1 week; (c) 20 minutes every day for 1 week. Treatments were well tolerated. A different increase in flux was observed on the basis of different treatments. Flux variations generally indicated that increased SWs dosage was associated with proportional flux increase. Flux improvement was still present after 4 weeks. SWs treatment in CLI produced changes both in the microcirculation and on pain. These preliminary results are comforting and open new research options to be explored in the near future.

Nomograms used to define the short-term treatment with PGE(1) in patients with intermittent claudication and critical ischemia. The ORACL.E (Occlusion Revascularization in the Atherosclerotic Critical Limb) Study Group. The European Study

Infusional, cyclic PGE1 treatment is effective in patients with intermittent claudication and critical limb ischemia (CLI). One of the problems related to chronic PGE1 treatment in vascular diseases due to atherosclerosis is to evaluate the variations of clinical conditions due to treatment in order to establish the number of cycles per year or per period (in severe vascular disease reevaluation of patients should be more frequent) needed to achieve clinical improvement. In a preliminary pilot study a group of 150 patients (mean age 67+/-12 years) with intermittent claudication (walking range from 0 to 500 m) and a group of 100 patients with CLI (45% with rest pain, and 55% gangrene; mean age 68 +/-11 years) the number of PGE1 cycles according to the short-term protocol (STP) needed to produce significant clinical improvement was preliminarily evaluated. Considering these preliminary observations, the investigators established a research plan useful to produce nomograms indicating the number of cycles of PGE1-STP per year needed to improve the clinical condition (both in intermittent claudication and CLI). A significant clinical improvement was arbitrarily defined as the increase of at least 35% in walking distance (on treadmill) and/or the disappearance of signs and symptoms of critical ischemia in 6 months of treatment in at least 75% of the treated patients. With consideration of the results obtained with the preliminary nomograms a larger validation of the nomograms is now advisable. A cost-effectiveness analysis is also useful to define the efficacy of treatment on the basis of its costs. The publication of this report in two angiological journals (Angeiologie and Angiology) will open the research on nomograms to all centers willing to collaborate to the study. The data are being collected in the ORACL.E database and will be analyzed within 12 months after the publication of this report.