Feasibility study of a mixed reality tool for real 3D visualization and planning of left atrial appendage occlusion.

In left atrial appendage occlusion (LAAO), pre-procedural imaging is pivotal to describe the highly variable LAA anatomy and to guide the operator in device sizing and interventional planning. Multiplanar reconstruction and 3D rendering are used for the interpretation of 3D CT datasets. However, this method of review of such imaging, which is mediated by 2D screens, may be limited due to the lack of true 3D visualization of the structures of interest; Mixed Reality (MxR) may further improve the CT-based pre-procedural planning by allowing for real-3D visualizations with holographic replicas of anatomical models. In this manuscript we present a novel software based on MxR and we evaluated its feasibility on different LAA morphologies. The morphological analysis of the holographic anatomical models was successfully applied for all the patients (n â€‹= â€‹4) independently from the morphology and it was performed in less than 10 minutes. Our findings suggest that with further developments MxR could have the potential to become a pivotal tool in LAA occlusion planning thanks to the real-3D perception, possibly leading to a more accurate and faster planning phase.

A statistical shape model of the left ventricle from real-time 3D echocardiography and its application to myocardial segmentation of cardiac magnetic resonance images.

OBJECT: We present in this paper the application of a statistical shape model of the left ventricle (LV) built from transthoracic real time 3D echocardiography (3DE) to segment the LV endocardium and epicardium in cardiac magnetic resonance (CMR) images. MATERIAL AND METHODS: The LV model was built from a training database constituted by over 9000 surfaces obtained from retrospectively selected 3DE examination of 435 patients with various pathologies. Three-dimensional segmentation of the endocardium and the epicardium was obtained by processing CMR images acquired in 30 patients with a dedicated active shape modelling (ASM) algorithm using the proposed LV model. RESULTS: The segmentation results obtained with the proposed method were compared with those obtained by the manual reference technique; similarity was proven by computing: i) point to surface distance (<2 mm), ii) Dice similarity coefficient (>89%), iii) Hausdorff distance (∼5 mm). This was furthermore confirmed by equivalence testing, linear regression and Bland Altman analysis applied on derived clinical parameters, such as LV volumes and mass. CONCLUSIONS: This study showed the potential usefulness of the proposed inter-modal ASM approach featuring a 3DE-based LV model for the 3D segmentation of the LV myocardium in CMR images.

P594Contrast transthoracic echocardiography as a gatekeeper for patent foramen ovale closure.

BACKGROUND.: The presence of patent foramen ovale (PFO) has been linked to many illness, including cryptogenic stroke, transient ischemic attack, migraine, platypnea-orthodeoxia syndrome and decompression sickness in scuba divers. Transesophageal echocardiography is the gold standard technique for the visualization of atrial septal anatomy, but it is a secondary level exam, not always available, with additional associated costs and not completely free from procedural risks. Standard transthoracic echocardiography (TTE) has a too low sensitivity for PFO screening. PURPOSE.: The aim of the study was to assess the role of TTE associated with agitated saline contrast injection (contrast-TTE) as a gatekeeper for the identification of PFO in a large cohort of patients undergoing selection for percutaneous closure. METHODS.: A total of 200 patients undergoing a diagnostic work-up for the identification of PFO was imaged by contrast-TTE at rest and after provocative maneuvers (PM: Valsalva in all cases). Contrast TTE was graded from 0 to 4 on the bases of bubbles counting (0: no bubbles; 1: < 10 bubbles; 2: 10-30 bubbles; 3: >30 bubbles; 4: complete LV opacification). PFO closure was performed after a consensual clinical decision by the cardiologist and the neurologist taking into account comprehensive imaging, clinical evaluation and thrombophilia screening. PFO closure was always monitored by intracardiac echocardiography. RESULTS.: At baseline contrast TTE was positive (≥2) in 34 patients (17%) while contrast TTE with PM was positive in 94 cases (47%). 27 out of 200 patients (14%) had an interatrial septal aneurysms. PFO closure was performed in 34 cases (17%). All of these had severe right-to-left shunting (≥3) at contrast TTE and 9 cases had also an interatrial septal aneurysms. The procedure was aborted in only 1 patient due to a complex defect anatomy. CONCLUSION.: Contrast TTE with PM may be not only considered an accurate tool for the detection of PFO but may be also inserted in the diagnostic work- up as a primary gatekeeper for percutaneous closure. Severe shunting at contrast TTE influences final decision making in a large cohort of cases undergoing screening for PFO closure.

Ultra-low-dose CT for left atrium and pulmonary veins imaging using new model-based iterative reconstruction algorithm.

AIMS: To evaluate the feasibility of ultra-low-dose CT for left atrium and pulmonary veins using new model-based iterative reconstruction (MBIR) algorithm. METHODS AND RESULTS: Two hundred patients scheduled for catheter ablation were randomized into two groups: Group 1 (100 patients, Multidetector row CT (MDCT) with MBIR, no ECG triggering, tube voltage and tube current of 100 kV and 60 mA, respectively) and Group 2 [100 patients, MDCT with adaptive statistical iterative reconstruction algorithm (ASIR), no ECG triggering, and kV and mA tailored on patient BMI]. Image quality, CT attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) of left atrium (LA) and pulmonary veins, and effective dose (ED) were evaluated for each exam and compared between two groups.No significant differences between groups in terms of population characteristics, cardiovascular risk factors, anatomical features, prevalence of persistent atrial fibrillation and image quality score. Statistically significant differences were found between Group 1 and Group 2 in mean attenuation, SNR, and CNR of LA. Significantly, lower values of noise were found in Group 1 versus Group 2. Group 1 showed a significantly lower mean ED in comparison with Group 2 (0.41 ± 0.04 versus 4.17 ± 2.7 mSv). CONCLUSION: The CT for LA and pulmonary veins imaging using MBIR is feasible and allows examinations with very low-radiation exposure without loss of image quality.

Sclerosing variant of PEComa: report of a case and review of the literature.

Tumours of perivascular epithelioid cells (PEComas) are a heterogeneous group of uncommon mesenchymal neoplasms which exhibit a peculiar immunohistochemical co-expression of muscle and melanocytic markers. PEComas occur at various visceral and soft tissue sites, generally with a benign clinical course. Nevertheless, there has been evidence of cases having an unfavourable outcome, thus prompting investigation of pathological criteria for malignancy. A sclerosing variant of PEComa, more frequently encountered in the retroperitoneum of middle-aged women, has been reported. Prognosis has generally been regarded as favourable and complete surgical excision appears to be adequate treatment. To the best of our knowledge, only two cases of sclerosing PEComa displayed high-grade malignant morphology and were associated with adverse outcome. An additional case of retroperitoneal sclerosing PEComa with a two-year follow-up and indolent behaviour is herein described. Light and electron microscopy were performed, along with immunohistochemical analysis. Further studies are needed to clarify the histogenesis and to predict the biological behaviour of this uncommon entity.

Feasibility and diagnostic accuracy of a low radiation exposure protocol for prospective ECG-triggering coronary MDCT angiography.

AIM: To compare the feasibility, accuracy, and effective radiation dose (ED) of multidetector computed tomography (MDCT) in the detection of coronary artery disease using a combined ED-saving strategy including prospective electrocardiogram (ECG) triggering with a short x-ray window and a body mass index (BMI)-adapted imaging protocol using adaptive statistical iterative reconstruction (ASIR; group 1), in comparison with a prospective ECG triggering strategy alone (group 2). MATERIALS AND METHODS: One hundred and seventy patients scheduled for invasive coronary angiography (ICA) were evaluated. Fourteen patients were not eligible for MDCT. The remaining 156 patients were randomized to group 1 (78 patients) and group 2 (78 patients). Eight and 11 patients in groups 1 and 2, respectively, were excluded after randomization because the patients' heart rates were >65 beats/min. MDCT images were assessed for feasibility, signal-to-noise ration (SNR), and contrast-to-noise ratio (CNR), accuracy in detection of coronary stenoses >50% versus ICA and for ED. RESULTS: The feasibility, SNR, CNR, accuracy in a segment-based and patient-based model were similar in both groups (97 versus 95%, 14.5 ± 3.9 versus 14.2 ± 4.1, 16 ± 4.6 versus 16.5 ± 4.4, 95 versus 94% and 97 versus 99%, respectively). The ED in group 1 was 72% lower than in group 2 (2.1 ± 1.2 versus 7.5 ± 1.8 mSv, respectively; p<0.01). CONCLUSIONS: The use of a multi-parametric ED saving protocol results in a significant reduction in ED without a negative impact on accuracy.

Arsenic-resistant Pseudomonas spp. and Bacillus sp. bacterial strains reducing As(V) to As(III), isolated from Alps soils, Italy.

Five arsenic-resistant bacterial strains (designated MP1400, MP1400a, MP1400d, APSLA3, and BPSLA3) were isolated from soils collected at the Alps region (Italy), which showed no contamination by arsenic. Phylogenetic analysis of the 16S rRNA gene sequences assigned them to the genera Pseudomonas and Bacillus. Bacillus sp. strain 1400d and Pseudomonas spp. strains APSLA3 and MP1400 showed higher tolerance to As(III), as indicated by minimum inhibitory concentrations of 10 mmol/L. Pseudomonas sp. strain MP1400 exhibited higher tolerance to As(V) (minimum inhibitory concentration of 135 mmol/L). The isolated arsenic-resistant strains were able to reduce As(V) to As(III), especially Pseudomonas sp. strain MP1400 reducing 2 mmol/L of As(V) to As(III) within 24 h. The results suggest that the isolated bacterial strains play a role in the arsenic biogeochemical cycle of arsenic-poor soils in the Alps mount area.

Arsenic precipitation by an anaerobic arsenic-respiring bacterial strain isolated from the polluted sediments of Orbetello Lagoon, Italy.

AIMS: To isolate and characterize an anaerobic bacterial strain from the deeper polluted lagoon sediment able to use as electron acceptors [As(V)] and sulfate (SO4(2-)), using lactate as an electron donor. METHODS AND RESULTS: Methods for isolation from polluted lagoon sediments included anaerobic enrichment cultures in the presence of As(V) and SO4(2-). Reduction of As(V) to As(III) was observed during the growth of the bacterial strain, and the final concentration of As(III) was lower than the initial As(V) one, suggesting the immobilization of As(III) in the yellow precipitate. The precipitate was identified by energy dispersive spectroscopy X-ray as arsenic sulfide. Scanning electron microscopy (SEM) revealed rod-shaped bacterial cells embedded in the precipitate, where net-like formations strictly related to the bacterial cells were visible. The surface of the precipitate showed the adhesion of bacterial cells, forming clusters. Transmission electron microscopy (TEM) also highlighted precipitates inside the bacterial cells and on their surface. Following 16S rRNA sequencing, the bacterial strain 063 was assigned to the genus Desulfosporosinus. CONCLUSIONS: This study reports, for the first time, the isolation from the polluted lagoon sediments of a strain capable of respiring and using As(V) and SO4(2-) as electron acceptors with lactate as the sole carbon and energy source with the formation of an arsenic sulfide precipitate. SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of these properties provides novel insight into the possible use of the anaerobic strain in bioremediation processes and also adds to the knowledge on the biogeochemical cycling of arsenic.

Recommendations for transoesophageal echocardiography: update 2010.

Transoesophageal echocardiography (TOE) is a standard and indispensable technique in clinical practice. The present recommendations represent an update and extension of the recommendations published in 2001 by the Working Group on Echocardiography of the European Society of Cardiology. New developments covered include technical advances such as 3D transoesophageal echo as well as developing applications such as transoesophageal echo in aortic valve repair and in valvular interventions, as well as a full section on perioperative TOE.

Intracardiac echocardiography in electrophysiology.

Intracardiac echocardiography (ICE) is a recent, invaluable tool which can provide real-time anatomical guidance in electrophysiological procedures. By inserting intravenously an ultrasound probe and advancing it into the heart, various different views can be obtained which allow to better visualize patient anatomy, to guide the placement of electrophysiological catheters, and to detect immediately procedural complications as they occur. In atrial fibrillation ablation, ICE proves particularly useful to achieve a safer trans-septal puncture (especially in the presence of anatomical anomalies of the interatrial septum) and to help to monitor the visualization of the mapping catheters (circular, high density), or the monitoring of the balloons catheter (Cryo, Laser) position. In ventricular tachycardia ablation, on the other hand, ICE allows for continuous correlation between electrophysiological and structural findings (such as wall motion anomalies or changes in echodensity), and helps to ensure correct catheter contact and to position it, particularly around delicate structures such as the aortic cusps. In any procedure, ICE is also useful to immediately detect procedural complications, such as thrombus formation along catheters, or pericardial effusion. Thanks to its real-time morphological information, ICE provides an ideal complement to simple fluoroscopy or to more complex electroanatomic mapping techniques and is set to gain a wider role in a broad range of electrophysiological procedures.

Arsenic-resistant bacteria isolated from contaminated sediments of the Orbetello Lagoon, Italy, and their characterization.

AIMS: The aim of this study was to isolate arsenic-resistant bacteria from contaminated sediment of the Orbetello Lagoon, Italy, to characterize isolates for As(III), As(V), heavy metals resistance, and from the phylogenetic point of view. METHODS AND RESULTS: Enrichment cultures were carried out in the presence of 6.75 mmol l(-1) of As(III), allowing isolation of ten bacterial strains. Four isolates, ORAs1, ORAs2, ORAs5 and ORAs6, showed minimum inhibitory concentration values equal or superior to 16.68 mmol l(-1) and 133.47 mmol l(-1) in the presence of As(III) and As(V), respectively. Isolate ORAs2 showed values of 1.8 mmol l(-1) in the presence of Cd(II) and 7.7 mmol l(-1) of Zn(II), and isolate ORAs1 pointed out a value of 8.0 mmol l(-1) in the presence of Cu(II). Analysis of 16S rRNA gene sequences revealed that they can be grouped in the three genera Aeromonas, Bacillus and Pseudomonas. Phylogenetic analysis of the four more arsenic-resistant strains was also performed. CONCLUSION: Isolates are highly resistant to both As(III) and As(V) and they could represent good candidates for bioremediation processes of native polluted sediments. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides original results on levels of resistance to arsenic and to assigning genera of bacterial strains isolated from arsenic-polluted sediments.

Accuracy of multidetector spiral computed tomography in detecting significant coronary stenosis in patient populations with differing pre-test probabilities of disease.

AIM: To investigate the clinical impact of multidetector computed tomography (MDCT) in patients with a low versus a high pre-test likelihood of coronary artery disease (CAD). MATERIALS AND METHODS: A cohort of 120 patients with suspected CAD, scheduled for conventional coronary angiography, underwent MDCT. Using the American Heart Association (AHA)/American College of Cardiology (ACC) guidelines, the population was divided into two groups: patients with a low (group 1) and a high (group 2) likelihood of CAD. RESULTS: Analysis of all segments showed a high feasibility (92%), and a patient based-model showed excellent sensitivity and negative predictive values (NPV; both 100%) and acceptable specificity and positive predictive values (PPV; 86 and 90%, respectively), with an accuracy of 94%. Using MDCT in patients with lower pre-test likelihoods of CAD, according to the ACC/AHA guidelines, the accuracy remained high (93%); conversely, in patient groups with a high prevalence of CAD, a non-significant reduction in accuracy (85%) occurred using MDCT. Particularly, MDCT can be used effectively to exclude a diagnosis of CAD because of its high sensitivity and NPV (100%), but shows a significant reduction in specificity (58%). This reduction was due to an increase in the false-positive:true-negative ratio because of the higher percentage of calcified plaque (a relative but non-significant increase in false positives), and the high prevalence of CAD (significant reduction in true negatives). No differences were found between MDCT and quantitative coronary angiography (QCA) concerning the number of vessels narrowed. CONCLUSION: Because of its excellent sensitivity and specificity in patients with a low pre-test likelihood of CAD, MDCT could be helpful in clinical decision-making in this population.

Inducible cyclooxygenase (COX-2) in glioblastoma--clinical and immunohistochemical (COX-2-VEGF) correlations.

Cyclooxygenase-2 (COX-2) is the inducible form of the enzyme responsible for the first step in the prostaglandin synthesis. COX-2 upregulation is demonstrated in different tumors. COX-2 products may modulate tumoral growth, apoptosis, metastasis, multidrug resistance and angiogenesis. Moreover, the antitumoral effect of the COX inhibitors has been documented. We studied the immunohistochemical expression and the prognostic value of COX-2 on 43 surgical specimens of glioblastoma-affected patients. Furthermore, we evaluated the correlation between the immunohistochemical expression of COX-2 and vascular endothelial growth factor (VEGF). Of the glioblastomas, 63% resulted as COX-2-positive. Median survival of the patients with COX-2-positive lesions was 10 months; median survival of the patients with COX-2 negative glioblastoma was 21 months (NS). All 4 patients who survived longer than 24 months had COX-2 negative lesions (p = 0.017). Concordance between COX-2 and VEGF was documented in 60% of the cases. Our findings show that glioblastoma can immunohistochemically express COX-2 and that its expression is unrelated with VEGF and significantly less frequent in the long survivors. Nevertheless, the absence of statistical correlation with survival time advises further studies on larger series to ascertain the concrete prognostic value of COX-2 in glioblastoma.

Usefulness of transoesophageal echocardiography before cardioversion in patients with atrial fibrillation and different anticoagulant regimens.

OBJECTIVES: To evaluate the prevalence of atrial thrombi in patients with atrial fibrillation undergoing different anticoagulation regimens before cardioversion; to evaluate the usefulness of transoesophageal echocardiography (TOE) guided cardioversion to prevent thromboembolic complications; and to correlate the presence of atrial thrombi with clinical and echocardiographic data. METHODS: 757 consecutive patients admitted as candidates for cardioversion of atrial fibrillation were enrolled in the study. They were divided into four groups: effective conventional oral anticoagulation, short term anticoagulation, ineffective oral anticoagulation or subtherapeutic anticoagulation, and effective oral anticoagulation with a duration of < 3 weeks for various clinical reasons. All patients underwent TOE before cardioversion; in the presence of atrial thrombi or extreme left atrial echo contrast, cardioversion was postponed. The incidence of thromboembolic events was evaluated after cardioversion. RESULTS: Atrial thrombi were detected in 48 of the 757 (6.3%) patients. No significant differences in the percentage of atrial thrombosis were found in the four study groups. Patients with atrial thrombosis were older and had a higher percentage of mitral prosthetic valves, lower left ventricular ejection fraction, more severe atrial spontaneous echo contrast, and lower Doppler left atrial appendage velocities. 648 patients were scheduled for cardioversion. Cardioversion was successful in 89% of patients without any major thromboembolic event. CONCLUSIONS: The prevalence of atrial thrombosis before cardioversion despite different treatments with anticoagulants is about 7% and a TOE guided approach may prevent the risk of embolic events.

Coronary blood flow, metabolism, and function in dysfunctional viable myocardium before and early after surgical revascularisation.

OBJECTIVES: To assess the link between perfusion, metabolism, and function in viable myocardium before and early after surgical revascularisation. DESIGN: Myocardial blood flow (MBF, thermodilution technique), metabolism (lactate, glucose, and free fatty acid extraction and fluxes), and function (transoesophageal echocardiography) were assessed in patients with critical stenosis of the left anterior descending coronary artery (LAD) before and 30 minutes after surgical revascularisation. SETTING: Tertiary cardiac centre. PATIENTS: 23 patients (mean (SEM) age 57 (1.7) years with LAD stenosis: 17 had dysfunctional viable myocardium in the LAD territory, as shown by thallium-201 rest redistribution and dobutamine stress echocardiography (group 1), and six had normally contracting myocardium (group 2). RESULTS: LAD MBF was lower in group 1 than in group 2 (58 (7) v 113 (21) ml/min, p < 0.001) before revascularisation and improved postoperatively in group 1 (129 (133) ml/min, p < 0.001) but not in group 2 (105 (20) ml/min, p = 0.26). Group 1 also had functional improvement in the LAD territory at intraoperative echocardiography (mean regional wall motion score from 2.6 (0.85) to 1.5 (0.98), p < 0.01). Oxidative metabolism, with lactate and free fatty acid extraction, was found preoperatively and postoperatively in both groups; however, lactate and free fatty acid uptake increased after revascularisation only in group 1. CONCLUSIONS: MBF is reduced and oxidative metabolism is preserved at rest in dysfunctional but viable myocardium. Surgical revascularisation yields immediate perfusion and functional improvement, and increases the uptake of lactate and free fatty acids.

[Atrial septal defect and transesophageal echocardiography. From the diagnosis to the monitoring of transcatheter closure]. / Ruolo dell'ecocardiografia transesofagea nella diagnosi del difetto del setto interatriale e nel monitoraggio della procedura di riparazione percutanea.

Atrial septal defect (ASD) is a common congenital heart disease representing 30% of congenital lesions in adults. Transcatheter closure has been regarded as an acceptable alternative treatment for patients with ASD. The prevalence of patent oval foramen (POF) is approximately 26% in autopsy and clinical studies, but it has been demonstrated that this prevalence is higher in patients with cryptogenic stroke. Even though the role of POF in the etiopathogenesis of cryptogenic stroke is debated, recurrent paradoxical embolism in the presence of POF associated with high motility of the membrane or with an atrial septal aneurysm is currently considered an indication for POF closure. This review covers the role of echocardiography (including transthoracic, transoesophageal and 3-dimensional methods) in the detection and diagnosis of these defects as well as the contribution of these techniques in the monitoring and follow-up of ASD and POF percutaneous closure.

Transcatheter treatment of coronary artery disease and atrial septal defect with sequential implantation of coronary stent and Amplatzer septal occluder: preliminary results.

Coronary stent implantation had been established as a highly effective revascularization technique in patients with occlusive coronary artery disease. Transcatheter closure of atrial septal defects is becoming a definite alternative to surgery in properly selected patients. During a 19-month period, 6 patients (50% women; mean age, 58 +/- 17 years; range, 32-73 years) of a consecutive series of 176 prospective multicenter registry patients undergoing transcatheter atrial septal defect closure were treated with sequential percutaneous coronary revascularization and Amplatzer septal occluder implantation. Indication for revascularization was stable angina in four patients and unstable angina in two. Indication for defect closure was significant left-to-right shunt with right ventricular enlargement. Defect diameter ranged from 13 to 20 mm by transesophageal echocardiography, and the stretched diameter measured 13 to 25 mm. Procedural success of both interventions was achieved in all cases without in-hospital complications. A total of seven stents were successfully implanted in five coronary vessels. No stent was used in one patient after successful PTCA. Immediate total closure of the defect was obtained in five patients. Trivial residual shunting, observed in one patient, disappeared at 24 hr. No adverse cardiac events, recurrence of anginal symptoms, or evidence of residual shunt were observed at clinical and echocardiographic follow-up, which ranged from 60 to 390 days (mean, 258 +/- 150 days). These results suggest that sequential transcatheter therapy of coronary artery disease and atrial septal defect is safe and efficacious in selected patients.

Giant anastomotic pseudoaneurysm after Bentall operation causing late postoperative cardiogenic shock.

Pseudoaneurysm of the ascending aorta is a rare but severe complication occurring after composite graft surgery for combined aortic valve and ascending aorta disease. The diagnosis of this condition can be difficult because anastomotic pseudoaneurysms show highly variable clinical features depending on the site of the aortic dehiscence and on the involvement of the surrounding structures. We report an unusual case of a late postoperative aortic graft dehiscence, causing acute right heart failure.

Gel sequestration of heavy metals by Klebsiella oxytoca isolated from iron mat.

The enterobacterium Klebsiella oxytoca strain BAS-10 was isolated from sediments under an iron mat formed in a stream receiving leached waters from pyrite mine tailings. Under anaerobic laboratory conditions, BAS-10 fermented Fe(III)-citrate and Na-citrate giving CH(3)COOH and CO(2). In the presence of ferric citrate, BAS-10 secreted quantities of a thick gel containing glucose and/or mannose, if not other sugars. Sugar residues were observed in microbial aggregates using the sugar-specific concanavalin A lectin conjugated with fluorescein and imaged by a scanning confocal laser microscope. The gel bound Fe(III) which quickly precipitated. During fermentation, however, half the initial Fe(III) concentration was reduced to Fe(II) which did not bind to the gel and remained in solution. BAS-10 showed a high tolerance to heavy metals. Its growth was not inhibited by 1 mM Zn-, Pb- or Cd-acetate. These cations also co-precipitated with the iron gel, suggesting a possible application of this strain for abatement of toxic metals under anaerobic conditions.

Lowering of blood pressure and coronary blood flow in isolated systolic hypertension.

BACKGROUND: In essential hypertension, the lower limit of autoregulation of coronary flow shifts to higher perfusion and the hypertensive ventricle is at a higher than normal risk of ischemia, and less able to tolerate acute reduction of coronary perfusion pressure. Little is known about pattern of coronary flow in isolated systolic hypertension, a pathologic condition in which the elevated systolic blood pressure is associated with a lower than normal vascular compliance and normal or slightly greater than normal mean arterial pressure and vascular resistance. OBJECTIVE: To evaluate the effects of rapid normalization of blood pressure on coronary blood flow in isolated systolic hypertension. METHODS: We subjected 20 patients with isolated systolic hypertension to intraoperative hemodynamic and transesophageal echocardiographic monitoring during peripheral vascular surgery. Coronary flow velocity integrals and diameters in the left anterior descending coronary artery were evaluated under baseline conditions and after normalization of blood pressure, which occurred spontaneously during anesthesia (10 cases; group 1A) or was induced by infusion of nitrate (10 cases, group 1B). RESULTS: After normalization of systolic blood pressure integrals decreased significantly only for patients in group 1A; percentage changes of diameter were significantly greater for patients in group 1B. Therefore, coronary blood flow after normalization of systolic blood pressure increased for patients in group 1B (by 28+/-25%) and decreased for patients in group 1A (by 30+/-21%). Changes in integrals were inversely related to those in diameter (r= -0.72, P < 0.001); for patients in group 1A changes in coronary perfusion pressure and diameter were related to those of integrals (r= 0.94; P < 0.0005). CONCLUSIONS: In isolated systolic hypertension, despite there being similar changes of the systolic blood pressure, administration of nitrates caused a marked increase of coronary flow through direct effects on coronary circulation, whereas spontaneous normotension was associated with a significant reduction of coronary flow.