Wrist band photoplethysmography in detection of individual pulses in atrial fibrillation and algorithm-based detection of atrial fibrillation.

AIMS: Atrial fibrillation (AF) is the most common tachyarrhythmia and a significant cause of cardioembolic strokes. Atrial fibrillation is often intermittent and asymptomatic making detection a major clinical challenge. We evaluated a photoplethysmography (PPG) wrist band in individual pulse detection in patients with AF and tested the reliability of two commonly used algorithms for AF detection. METHODS AND RESULTS: A 5-min PPG was recorded from patients with AF or sinus rhythm (SR) with a wrist band and analysed with two AF detection algorithms; AFEvidence and COSEn. Simultaneously registered electrocardiogram served as the golden standard for rhythm analysis and was interpreted by two cardiologists. The study population consisted of 213 (106 AF, 107 SR) patients. The wrist band PPG achieved individual pulse detection with a sensitivity of 91.7 ± 11.2% and a positive predictive value (PPV) of 97.5 ± 4.6% for AF, with a sensitivity of 99.4 ± 1.5% [7.7% (95% confidence interval, 95% CI 5.5% to 9.9%); P < 0.001] and PPV of 98.1 ± 4.1% [0.6% (95% CI -0.6% to 1.7%); P = 0.350] for SR. The pulse detection sensitivity was lower 86.7 ± 13.9% with recent-onset AF (AF duration <48 h, n = 43, 40.6%) as compared to late AF (≥48 h, n = 63, 59.4%) with 95.1 ± 7.2% [-8.3% (95% CI -12.9% to -3.7%); P = 0.001]. For the detection of AF from the wrist band PPG, the sensitivities were 96.2%/95.3% and specificity 98.1% with two algorithms. CONCLUSION: The wrist band PPG enabled accurate algorithm-based detection of AF with two AF detection algorithms and high individual pulse detection. Algorithms allowed accurate detection of AF from the PPG. A PPG wrist band provides an easy solution for AF screening.

Ultrasound Screening of Men with Coronary Artery Disease for Abdominal Aortic Aneurysms: A Prospective Dual Center Study.

BACKGROUND AND AIMS: According to the heterogeneous results of previous studies, the prevalence of abdominal aortic aneurysm seems high among men with coronary artery disease. The associating risk factors for abdominal aortic aneurysm in this population require clarification. Our objective was to assess the prevalence of non-diagnosed abdominal aortic aneurysms in men with angiographically verified coronary artery disease and to document the associated co-morbidities and risk factors. MATERIAL AND METHODS: Altogether, 407 men with coronary artery disease were screened after invasive coronary angiography in two series at independent centers. Risk factor data were recorded and analyzed. RESULTS AND CONCLUSION: The mean age of the study cohort was 70.0 years (standard deviation: 11.0). The prevalence of previously undiagnosed abdominal aortic aneurysms in the whole screened population of 407 men was 6.1% (n = 25/407). In a multivariate analysis of the whole study population, the only significant risk factors for abdominal aortic aneurysm were age (odds ratio: 1.04, 95% confidence interval: 1.00-1.09) and history of smoking (odds ratio: 3.13, 95% confidence interval: 1.26-7.80). Non-smokers with abdominal aortic aneurysm were significantly older than smokers (mean age: 80.7 (standard deviation: 8.0) vs 68.0 (standard deviation: 11.1), p = 0.003), and age was a significant risk factor only among non-smokers (p = 0.011; p = 0.018 for interaction). Among smokers, the prevalence of abdominal aortic aneurysm was 8.8%, and 72% (n = 18/25) of all diagnosed abdominal aortic aneurysm patients were smokers. Prevalence of undiagnosed abdominal aortic aneurysms among patients with coronary artery disease is high, and history of smoking is the most significant risk factor for abdominal aortic aneurysm. Effectiveness of selective screening of abdominal aortic aneurysm in male patients with coronary artery disease warrants further studies.

Long-term VEGF-A expression promotes aberrant angiogenesis and fibrosis in skeletal muscle.

Vascular endothelial growth factor A (VEGF-A) induces strong angiogenesis and it has been widely used in proangiogenic gene therapy studies. However, little is known about long-term effects of VEGF-A expression in skeletal muscle. Here the long- term effects of adeno-associated virus (AAV) encoding human VEGF-A(165) (AAV-VEGF-A) gene transfer in normal and ischemic rabbit hindlimb skeletal muscles were studied. AAV-LacZ was used as a control. In one-year follow-up, a remarkable increase in skeletal muscle perfusion compared with AAV-LacZ was observed measured with Doppler and contrast pulse sequence ultrasound. Angiogenesis was also seen in histology as enlarged and sprouting capillaries. In addition to favorable angiogenic effects, aberrant vascular structures with CD31 positive cell layers were seen inside muscle fibers after AAV-VEGF-A gene transfer. Importantly, we found increased amounts of extracellular matrix with a high number of macrophages and fibrosis in AAV-VEGF-A transduced muscles. No changes in skeletal muscle morphology were detected in AAV-LacZ transduced muscles. Our results indicate that local AAV-VEGF-A gene transfer efficiently promotes long-term angiogenesis in large animal model. However, non-regulated expression of VEGF-A causes unfavorable changes in muscle morphology, which suggests the need for regulation of the transgene expression in long-term AAV-mediated VEGF-A gene transfer applications.

Overexpression of VEGF-A induces neovascularization and increased vascular leakage in rabbit eye after intravitreal adenoviral gene transfer.

AIM: The aim of this study was to determine dose-response effects of vascular endothelial growth factor A as delivered using an adenoviral vector on vascular growth and pathological changes in the rabbit eye. Moreover, we wanted to develop a large animal model for angioproliferative diseases in the eye. METHODS: Seventeen New Zealand White rabbits were injected with adenoviral vascular endothelial growth factor-A (AdVEGF-A) intravitreally with different doses (10(9)-10(11) vp). Controls were injected with an empty virus (AdCMV). Some animals had a combination of AdVEGF-A and AdsKDR (a soluble form of the VEGF receptor-2). Animals were killed 6 days after the gene transfer. On the basis of these results, 14 rabbits were injected intravitreally with AdVEGF-A or adenoviral LacZ (AdLacZ) with 10(10) vp in a volume of 0.1 mL. Animals were killed 3, 6, 14 and 28 days after the gene transfer, eyes were removed and analysed histologically. RESULTS: In enzyme-linked immunosorbent assay (ELISA) analysis, human VEGF-A was present in vitreous humour in all VEGF-A transduced eyes. The amount of VEGF-A showed a dose-dependent increase with the AdVEGF-A dose and was the highest 6 days after the gene transfer. Histologic analyses revealed an increased capillary area and density in the AdVEGF-A eyes when compared with the AdLacZ eyes (P < 0.05). In the AdVEGF-A/AdsKDR eyes the average capillary area was not increased compared with AdLacZ eyes. CONCLUSION: This model could be useful for large animal studies regarding the pathogenesis of neoangiogenesis and for the development of new therapeutic strategies for angioproliferative diseases of the eye. Our results establish the key role of VEGF-A in the induction of neovascularization and pathological changes in the rabbit eye.

Gene transfer using the mature form of VEGF-D reduces neointimal thickening through nitric oxide-dependent mechanism.

Gene transfer to the vessel wall using vascular endothelial growth factors (VEGFs) has shown therapeutic potential for the treatment of restenosis. In this study, we evaluated the effect of catheter-mediated adenoviral (Ad) gene transfer of the mature form of VEGF-D (VEGF-D(DeltaNDeltaC)) in balloon-denuded cholesterol-fed rabbit aorta. AdLacZ was used as a control. Transduced VEGF-D(DeltaNDeltaC) mRNA was detectable in the arterial wall with RT-PCR at 6, 14 and 28 days. Gene transfer efficiency as detected with X-gal staining 6 days after the AdLacZ transduction was 1.91 +/- 1.32% in intima. AdVEGF-D(DeltaNDeltaC) gene transfer led to 52% reduction in intima/media ratio (I/M) as compared to the AdLacZ controls at 14 days time point. At 6 days there were no differences in I/M, but the number of macrophages in the vessel wall was 85% lower in the AdVEGF-D(DeltaNDeltaC) group as compared to the controls. The therapeutic effect was no longer detectable 28 days after the gene transfer. The therapeutic effect of VEGF-D(DeltaNDeltaC) was nitric oxide (NO)-dependent as the feeding of NO synthase inhibitor, L-NAME, blocked the reduction in intimal thickening. It is concluded that AdVEGF-D(DeltaNDeltaC) gene transfer reduces intimal thickening and macrophage influx into the vessel wall in balloon-denuded rabbit aortas.

Angiogenesis, vascular endothelial growth factor and platelet-derived growth factor-BB expression, iron deposition, and oxidation-specific epitopes in stented human coronary arteries.

Pathogenesis of in-stent restenosis remains poorly understood because information from human histopathologic studies is scarce. We used an improved saw-grinding and cutting method on methacrylate-embedded samples containing metal stents, which allows in situ hybridization and immunohistochemical analysis of in-stent restenosis. Twenty-one samples were collected 3 hours to 3 years after stenting from 6 patients aged 36 to 81 years. Except in very early samples collected within hours after the stent deployment, neovascularization was present in all segments studied. At advanced stages, extensive neovascularization was located mainly at the luminal side of the stent struts and was only rarely accompanied by inflammatory cells. The neovessels colocalized with vascular endothelial growth factor (VEGF)-A mRNA and protein expression as well as with iron deposits and oxidation-specific epitopes, which imply the presence of chronic oxidative stress. VEGF-A expression was detected in the same areas containing macrophages, endothelial cells, and, to a lesser extent, smooth muscle cells, which also showed platelet-derived growth factor-BB expression. We conclude that in-stent restenosis features neovascularization, VEGF-A and platelet-derived growth factor-BB expression, and iron deposition, which is most probably derived from microhemorrhages. These mechanisms may play an important role in the development of neointimal thickening and could provide useful targets for the prevention and treatment of in-stent restenosis.

Gene therapy for therapeutic angiogenesis in critically ischaemic lower limb - on the way to the clinic.

Currently, no effective pharmacological treatment is available for vascularisation defects in lower limbs. Many patients presenting with persistent pain and ischaemic ulcers are not suitable candidates for surgical or endovascular approaches. Further refinement of the available methods will undoubtedly lead to a more active approach towards treatment of peripheral arterial occlusive disease (PAOD). Recently, therapeutic angiogenesis, in the form of recombinant growth factor administration or gene therapy, has emerged as a novel tool to treat these patients. However, improved gene transfer methods and better understanding of blood vessel formation are required to bring therapeutic angiogenesis to clinical practice. Here we review the clinical problem (PAOD), mechanisms of blood vessel formation (angiogenesis, vasculogenesis and arteriogenesis), experimental evidence and clinical trials for therapeutic angiogenesis in critically ischaemic lower limbs. Also, angiogenic growth factors, including vascular endothelial growth factors (VEGFs) and fibroblast growth factors (FGFs), delivery methods, and vectors for gene transfer in skeletal muscle, are discussed. In addition to vascular growth, gene transfer of growth factors may enhance regeneration, survival, and innervation of ischaemic skeletal muscle. Nitric oxide (NO) appears to be a key mediator in vascular homeostasis and growth, and a reduction in its production by age, hypercholesterolemia or diabetes leads to the impairment of ischaemic disorders.

Angiographically guided utero-placental gene transfer in rabbits with adenoviruses, plasmid/liposomes and plasmid/polyethyleneimine complexes.

We examined the feasibility of gene transfer to rabbit placenta using adenoviruses, plasmid/liposomes and plasmid/polyethyleneimine (PEI) complexes. Pregnant New Zealand White rabbits (n = 17) were anesthetized and local gene transfer was done via a catheter inserted in uterine arteries under direct angiographic control. Either nuclear targeted LacZ adenoviruses (1.0 x 10(10) p.f.u.), nuclear targeted LacZ plasmid (500 microg)/liposome (DOTMA:DOPE 1:1) complexes or nuclear targeted LacZ plasmid (250 microg)/PEI (25 kDa) complexes (charge ratio +/-4) were used. Animals were killed 3 days later and detection of the transgene expression was done by X-gal staining and RT-PCR. Adenovirus-mediated gene transfer resulted in a high transfection efficiency (34 +/- 10%) in placental trophoplastic cells. Very little, if any, transfection was seen in fetal membranes. Plasmid/liposomes and plasmid/PEI complexes led to a very low (<0.01%) transfection efficiency in trophoblastic cells, but some transfection was seen in fetal membranes. A total of 25 fetuses were analyzed for the presence of transgene at the time of death. In most fetuses expression of the LacZ gene was below the sensitivity of the X-gal staining, but expression was detected by PCR in 50%, 50% and 42% of the analyzed fetuses after adenoviral, plasmid/PEI and plasmid/liposome gene transfer, respectively. No major inflammatory changes were present in the transfected placentas as analyzed by general histology and macrophage- and T cell-specific immunostainings. We conclude that catheter-mediated intravascular gene transfer with adenoviruses can be used for the transfection of placental trophoplastic cells, but plasmid complexes are inefficient for this purpose. However, selective angiographically guided gene transfer also led to leakage of the vector to fetuses. Therefore, if gene therapy is developed for the treatment of placental disorders, the gene-vector combination should not be harmful to the fetus and the expression of the transgene should only occur in placenta.

Clinical applications of vascular gene therapy.

Despite significant advances in prevention, coronary artery disease remains the leading cause of death in the Western world. Surgical bypass and angioplasty are the primary interventional therapies but they are limited by the problems of restenosis and graft occlusions. Natural response to vascular occlusion involves the formation of collateral vessels that bypass obstructions, but they are often inefficient in relieving ischemia. Vascular gene transfer offers a promising new approach to solve these problems. Its potential has been shown in animal models and in first human trials using vascular endothelial growth factor, fibroblast growth factor, and E2F cell-cycle transcription factor decoy. However, further basic research on gene transfer vectors, gene delivery techniques, and identification of effective treatment genes is needed to improve the efficacy and safety of human vascular gene therapy.

Intravascular adenovirus-mediated VEGF-C gene transfer reduces neointima formation in balloon-denuded rabbit aorta.

BACKGROUND: Gene transfer to the vessel wall may provide new possibilities for the treatment of vascular disorders, such as postangioplasty restenosis. In this study, we analyzed the effects of adenovirus-mediated vascular endothelial growth factor (VEGF)-C gene transfer on neointima formation after endothelial denudation in rabbits. For comparison, a second group was treated with VEGF-A adenovirus and a third group with lacZ adenovirus. Clinical-grade adenoviruses were used for the study. METHODS AND RESULTS: Aortas of cholesterol-fed New Zealand White rabbits were balloon-denuded, and gene transfer was performed 3 days later. Animals were euthanized 2 and 4 weeks after the gene transfer, and intima/media ratio (I/M), histology, and cell proliferation were analyzed. Two weeks after the gene transfer, I/M in the lacZ-transfected control group was 0. 57+/-0.04. VEGF-C gene transfer reduced I/M to 0.38+/-0.02 (P:<0.05 versus lacZ group). I/M in VEGF-A-treated animals was 0.49+/-0.17 (P:=NS). The tendency that both VEGF groups had smaller I/M persisted at the 4-week time point, when the lacZ group had an I/M of 0.73+/-0.16, the VEGF-C group 0.44+/-0.14, and the VEGF-A group 0. 63+/-0.21 (P:=NS). Expression of VEGF receptors 1, 2, and 3 was detected in the vessel wall by immunocytochemistry and in situ hybridization. As an additional control, the effect of adenovirus on cell proliferation was analyzed by performing gene transfer to intact aorta without endothelial denudation. No differences were seen in smooth muscle cell proliferation or I/M between lacZ adenovirus and 0.9% saline-treated animals. CONCLUSIONS: Adenovirus-mediated VEGF-C gene transfer may be useful for the treatment of postangioplasty restenosis and vessel wall thickening after vascular manipulations.

Biodistribution of adenoviral vector to nontarget tissues after local in vivo gene transfer to arterial wall using intravascular and periadventitial gene delivery methods.

Expression of transgene other than in the target tissue may cause side effects and safety problems in gene therapy. We analyzed biodistribution of transgene expression after intravascular and periadventitial gene delivery methods using the first generation nuclear-targeted lacZ adenovirus. RT-PCR and X-Gal stainings were used to study transgene expression 14 days after the gene transfer. After intravascular catheter-mediated gene transfer to rabbit aorta mimicking angioplasty procedure, the target vessel showed 1.1% +/- 0. 5 gene transfer efficiency. Other tissues showed varying lacZ gene expression indicating a systemic leakage of the vector with the highest transfection efficiency in hepatocytes (0.7% +/- 0.5). X-Gal staining of blood cells 24 h after the intravascular gene transfer indicated that a significant portion (1.8% +/- 0.8) of circulating monocytes was transfected. X-Gal-positive cells were also found in testis. After periadventitial gene transfer using a closed silicon capsule placed around the artery, 0.1% +/- 0.1 lacZ-positive cells were detected in the artery wall. Positive cells were also found in the liver and testis (<0.01%), indicating that the virus escapes even from the periadventitial space, although less extensively than during the intravascular application. We conclude that catheter-mediated intravascular and, to a lesser extent, periadventitial gene transfer lead to leakage of adenovirus to systemic circulation, followed by expression of the transgene in several tissues. Possible consequences of the ectopic expression of the transgene should be evaluated in gene therapy trials even if local gene delivery methods are used.