Malignant Hypertension:A Systemic Cardiovascular Disease: JACC Review Topic of the Week.

Malignant hypertension (MHT) is a hypertensive emergency with excessive blood pressure (BP) elevation and accelerated disease progression. MHT is characterized by acute microvascular damage and autoregulation failure affecting the retina, brain, heart, kidney, and vascular tree. BP must be lowered within hours to mitigate patient risk. Both absolute BP levels and the pace of BP rise determine risk of target-organ damage. Nonadherence to the antihypertensive regimen remains the most common cause for MHT, although antiangiogenic and immunosuppressant therapy can also trigger hypertensive emergencies. Depending on the clinical presentation, parenteral or oral therapy can be used to initiate BP lowering. Evidence-based outcome data are spotty or lacking in MHT. With effective treatment, the prognosis for MHT has improved; however, patients remain at high risk of adverse cardiovascular and kidney outcomes. In this review, we summarize current viewpoints on the epidemiology, pathogenesis, and management of MHT; highlight research gaps; and propose strategies to improve outcomes.

Immunological alterations in intracranial aneurysm: a prospective study on selected biomarker profiles in blood collected during endovascular neurointervention.

INTRODUCTION: Previous studies showed that the concentrations of selected chemokines are locally elevated in samples collected from the lumen of intracranial aneurysms (IA). Our objective was to determine whether the observed differences in analyte concentrations were influenced by the origin of the blood samples (i.e. cerebral versus peripheral), thus providing insight into the localised nature of these alterations and their significance in IA pathogenesis. MATERIAL AND METHODS: This prospective study included 24 patients with IA who underwent endovascular embolisation. Concentrations of selected analytes were analysed in blood samples from the IA lumen, feeding artery, and aorta. The analytes included MPO, Lipocalin-2/NGAL, sICAM-1, sVCAM-1, and serum amyloid A. RESULTS: Higher median plasma concentrations of MPO, lipocalin-2/NGAL, sVCAM-1, and SAA were found in samples obtained from the IA lumen and the feeding artery compared to the aorta. The concentration of sICAM-1 was significantly higher in the IA compared to the aorta, but did not differ between the proximal artery and the aorta. No significant differences in any analyte concentration were observed between the IA and the proximal artery. CONCLUSIONS: These findings suggest that the IA and the proximal vessel share similarities in the local immunological environment, which is different from that observed in the aorta. Further studies are needed to fully understand and elucidate these observations.

Risks and benefits of renal artery stenting in fibromuscular dysplasia: Lessons from the ARCADIA-POL study.

INTRODUCTION: Although renal stenting is the standard revascularization method for atherosclerotic renal artery stenosis (RAS) (FMD-RAS), stenting in fibromuscular dysplasia (FMD) RAS is usually limited to periprocedural complications of angioplasty and primary arterial dissection. The main aim of the study was to retrospectively analyze the immediate and long-term results of renal stenting versus angioplasty in patients with FMD. METHODS: Of 343 patients in the ARCADIA-POL registry, 58 patients underwent percutaneous treatment due to FMD-RAS (in 70 arteries). Percutaneous transluminal renal angioplasty (PTRA) was performed as an initial treatment in 61 arteries (PTRA-group), whereas primary stenting was undertaken in nine arteries (stent-group). Stent-related complications were defined as: in-stent restenosis > 50% (ISR); stent fracture; under-expansion; or migration. RESULTS: In the PTRA-group, the initial restenosis rate was 50.8%. A second procedure was then performed in 22 arteries: re-PTRA (12 arteries) or stenting (10 arteries). The incidence of recurrent restenosis after re-PTRA was 41.7%. Complications occurred in seven of 10 (70%) arteries secondarily treated by stenting: two with under-expansion and five with ISR. In the stent-group, stent under-expansion occurred in one case (11.1%) and ISR in three of nine stents (33.3%). In combined analysis of stented arteries, either primarily or secondarily, stent-related complications occurred in 11/19 stenting procedures (57.9%): three due to under-expansion and eight due to ISRs. Finally, despite several revascularization attempts, four of 19 (21%) stented arteries were totally occluded and one was significantly stenosed at follow-up imaging. CONCLUSION: Our study indicates that renal stenting in FMD-RAS may carry a high risk of late complications, including stent occlusion. Further observational data from large-scale registries are required.

Comparison of Computed Tomography Scoring Systems in Patients with COVID-19 and Hematological Malignancies.

BACKGROUND: Numerous computed tomography (CT) scales have been proposed to assess lung involvement in COVID-19 pneumonia as well as correlate radiological findings with patient outcomes. OBJECTIVE: Comparison of different CT scoring systems in terms of time consumption and diagnostic performance in patients with hematological malignancies and COVID-19 infection. MATERIALS AND METHODS: Retrospective analysis included hematological patients with COVID-19 and CT performed within 10 days of diagnosis of infection. CT scans were analyzed in three different semi-quantitative scoring systems, Chest CT Severity Score (CT-SS), Chest CT Score(CT-S), amd Total Severity Score (TSS), as well as qualitative modified Total Severity Score (m-TSS). Time consumption and diagnostic performance were analyzed. RESULTS: Fifty hematological patients were included. Based on the ICC values, excellent inter-observer reliability was found among the three semi-quantitative methods with ICC > 0.9 (p < 0.001). The inter-observer concordance was at the level of perfect agreement (kappa value = 1) for the mTSS method (p < 0.001). The three-receiver operating characteristic (ROC) curves revealed excellent and very good diagnostic accuracy for the three quantitative scoring systems. The AUC values were excellent (0.902), very good (0.899), and very good (0.881) in the CT-SS, CT-S and TSS scoring systems, respectively. Sensitivity showed high levels at 72.7%, 75%, and 65.9%, respectively, and specificity was recorded at 98.2%, 100%, 94.6% for the CT-SS, CT-S, and TSS scoring systems, respectively. Time consumption was the same for Chest CT Severity Score and TSS and was longer for Chest CT Score (p < 0.001). CONCLUSIONS: Chest CT score and chest CT severity score have very high sensitivity and specificity in terms of diagnostic accuracy. The highest AUC values and the shortest median time of analysis in chest CT severity score indicate this method as preferred for semi-quantitative assessment of chest CT in hematological patients with COVID-19.

Can Color Doppler Ultrasound Be Effectively Used as the Follow-Up Modality in Patients Undergoing Splenic Artery Aneurysm Embolization? A Correlational Study between Doppler Ultrasound, Magnetic Resonance Angiography and Digital Subtraction Angiography.

Splenic artery aneurysm (SAAs) rupture is associated with a high mortality rate. Regular surveillance with imaging before and after intervention is crucial to guide best evidence treatment. The following study aimed to determine the efficacy of color Doppler ultrasound imaging (DUS) compared to digital subtraction angiography (DSA) and magnetic resonance angiography (MRA) as a follow-up modality after selective coil embolization of true SAAs. We analyzed data from 20 patients, 15 females (48.1 ± 16.1 years) undergoing selective SAA coil embolization using detachable fibered embolization coils. Imaging using DUS, MRA, and DSA was performed 3 months after the initial embolization or the consequent re-embolization procedure. Primary clinical success, defined as Class I aneurysm occlusion, on 3-month follow-up was seen in 16 (80.0%) patients. DUS had a sensitivity of 94.4% and a specificity of 42.9% when compared to DSA and 92.3% and 30%, respectively, when compared to MRA in identifying Class I aneurysm occlusion. The positive predictive value (PPV) of DUS in identifying the need for re-embolization was 75.0%, while the NPV of DUS in these terms was 90.5%. DUS showed a high sensitivity in detecting aneurysm occlusion and clinical success, simultaneously exhibiting poor specificity. Still, with caution, this follow-up modality could be used for monitoring select low-risk patients after selective embolization of SAAs. DUS could provide a higher cost-to-benefit ratio, enabling more systematic post-procedural follow-up, as it is far more commonly used compared to MRA and non-invasive compared to DSA.

Atherosclerotic renovascular disease and cardiovascular risk: new concepts.

Renal vascular hypertension (RVHT) is one of the most common secondary forms of hypertension. It is estimated that 1% to 5% of all cases of hypertension can be attributed to RVHT. RVHT is generally caused by progressive stenosis of the renal artery most often due to atherosclerosis, and less often caused by fibromuscular dysplasia. Atherosclerotic renal artery stenosis (ARAS) can lead to the development of resistant hypertension and can also cause progressive impairment of renal function. ARAS can also result in serious cardiac complications, such as flash pulmonary edema or congestive heart failure. Most patients with ARAS are characterized by the presence of left ventricular hypertrophy and diastolic dysfunction. The disease progression is associated with an increase in left ventricular mass index and cardiac dilatation. Atherosclerotic renovascular disease is recognized as a relevant risk factor for cardiovascular morbidity and mortality. Studies published so far documented ARAS as a predictor of higher cardiovascular risk and showed that mortality after incidental ARAS diagnosis is much higher than that observed in the general population. Proper recognition of the patients with ARAS who would benefit from interventional treatment is crucial, particularly for identification of patients with true resistant hypertension, flash pulmonary edema, and progressive impairment of renal function.

Cardiac Phenotypes in Secondary Hypertension: JACC State-of-the-Art Review.

Several forms of secondary hypertension carry a high risk of cardiac morbidity and mortality. Evaluation of cardiac phenotypes in secondary hypertension provides a unique opportunity to study underlying hormonal and biochemical mechanisms affecting the heart. We review the characteristics of cardiac dysfunction in different forms of secondary hypertension and clarify the mechanisms behind the higher prevalence of heart damage in these patients than in those with primary hypertension. Attention to the specific clinical/biochemical phenotypes of these conditions may assist clinicians to screen for and confirm secondary forms of hypertension. Thereby, early signs of heart damage can be recognized and monitored, allowing individualized treatment to delay or prevent evolution toward more advanced disease.

Transplant Renal Artery Stenosis: Underrecognized, Not So Rare, but Curable Complication.

Transplant renal artery stenosis (TRAS) constitutes 75% of all vascular complications in kidney transplant recipients, being a significant source of graft dysfunction and loss. TRAS is a heterogeneous disease with different risk factors and causes. The incidence differs greatly, and it is likely it will increase because of the aging population of potential recipients and donors of renal grafts and the expanding use of extended-criteria donors. Prompt diagnosis and treatment of TRAS can prevent irreversible allograft dysfunction and loss. Current evidence of risk factors, diagnostic challenges, and therapeutic options are presented in this short review.

Current progress in clinical, molecular, and genetic aspects of adult fibromuscular dysplasia.

Fibromuscular dysplasia (FMD) is a non-atherosclerotic vascular disease that may involve medium-sized muscular arteries throughout the body. The majority of FMD patients are women. Although a variety of genetic, mechanical, and hormonal factors play a role in the pathogenesis of FMD, overall, its cause remains poorly understood. It is probable that the pathogenesis of FMD is linked to a combination of genetic and environmental factors. Extensive studies have correlated the arterial lesions of FMD to histopathological findings of arterial fibrosis, cellular hyperplasia, and distortion of the abnormal architecture of the arterial wall. More recently, the vascular phenotype of lesions associated with FMD has been expanded to include arterial aneurysms, dissections, and tortuosity. However, in the absence of a string-of-beads or focal stenosis, these lesions do not suffice to establish the diagnosis. While FMD most commonly involves renal and cerebrovascular arteries, involvement of most arteries throughout the body has been reported. Increasing evidence highlights that FMD is a systemic arterial disease and that subclinical alterations can be found in non-affected arterial segments. Recent significant progress in FMD-related research has led to improve our understanding of the disease's clinical manifestations, natural history, epidemiology, and genetics. Ongoing work continues to focus on FMD genetics and proteomics, physiological effects of FMD on cardiovascular structure and function, and novel imaging modalities and blood-based biomarkers that can be used to identify subclinical FMD. It is also hoped that the next decade will bring the development of multi-centred and potentially international clinical trials to provide comparative effectiveness data to inform the optimal management of patients with FMD.

Th17/Treg imbalance in patients with primary hyperaldosteronism and resistant hypertension.

INTRODUCTION: Inflammation plays a pivotal role in blood pressure regulation. Data on experimental models of hypertension and hypertensive patients reflect the imbalance between T regulatory (Treg) and Th17 effector cells (Th17). OBJECTIVES: The aim of this study was to quantify peripheral blood Treg lymphocytes and Th17 subsets in individuals with primary hyperaldosteronism (PHA) and resistant hypertension (RHT) presenting with elevated blood pressure levels and augmented cardiovascular risk when compared with normotensive controls (CTRL). PATIENTS AND METHODS: Twenty CTRL participants, 21 patients with PHA, and 20 patients with RHT were enrolled. Plasma renin and angiotensin II, serum aldosterone concentration, ambulatory blood pressure monitoring (ABPM), echocardiography, clinical data, and phenotype of peripheral blood cells were assessed. RESULTS: There were no statistically significant differences in terms of age and sex between the groups. Similar systolic blood pressure (SBP) and diastolic blood pressure (DBP) levels in ABPM were observed in individuals with PHA and RHT. PHA patients had lower angiotensin II and 4­fold higher aldosterone concentrations than CTRL patients. Both, PHA and RHT were associated with cardiac hypertrophy and coronary artery disease. RHT patients presented a significantly higher CD4+IL­17A+ T cell number when compared with PHA and CTRL ones. The number of CD4+CD25+FOXP3+ T cells did not differ between patients with secondary hypertension and normotensive controls. Finally, positive correlations between the data on 24 h SBP and the content of CD4+IL­17A+ and CD4+CD25+FOXP3+ in the PHA were found. CONCLUSIONS: Elevated 24 h SBP in PHA was associated with the increased numbers of CD4+IL­17 and CD4+CD25+FOXP3+ T cells.

Intrarenal hemodynamics and kidney function in pheochromocytoma and paraganglioma before and after surgical treatment.

PURPOSE: Current evidence regarding renal involvement in pheochromocytoma and paraganglioma (PPGL) is scant. More accurate diagnostic methods, such as renal Doppler ultrasound for intrarenal hemodynamic studies, may provide more detailed information on renal function. It might be postulated that renal function in PPGL patients might be altered by high blood pressure and excess secretion of catecholamines. The aim of this prospective study was to assess intrarenal blood flow parameters in PPGL patients included in the prospective monoamine-producing tumour (PMT) study and to evaluate the effects of normalisation of catecholamine production after surgical treatment on long-term renal function. MATERIALS AND METHODS: Seventy consecutive patients (aged 46.5 ± 14.0 years) with PPGL were included. Forty-eight patients from the PMT study cohort, matched for age, gender, blood pressure level and presence of hypertension, served as a control group. Renal artery doppler ultrasound spectral analysis included mean resistance index (RRI) and pulsatility index (PI). Forty-seven patients completed 12 months follow-up. RESULTS: There were no differences in renal parameters such as RRI, PI and kidney function between PPGL and non-PPGL patients as assessed by renal ultrasound, serum creatinine, eGFR and albumin excretion rate. No correlations between kidney function parameters, intrarenal doppler flow parameters and plasma catecholamines were observed in PPGL patients. At 12 months after surgery, no differences in creatinine level, eGFR, albumin excretion rate, RI and PI were found as compared to baseline results. CONCLUSIONS: In contrast to patients with other forms of secondary hypertension, our study did not show differences in intrarenal blood flow parameters and renal function between PPGL and non-PPGL subjects. Intrarenal hemodynamics and renal function did not change after normalisation of catecholamine levels by surgical treatment.

Longitudinal changes in maternal left atrial volume index and uterine artery pulsatility indices in uncomplicated pregnancy.

BACKGROUND: Data on the relationship between longitudinal changes in maternal volume-dependent echocardiographic parameters and placentation in uncomplicated pregnancy are limited. OBJECTIVE: This study aimed to evaluate changes in volume-dependent echocardiographic parameters in uncomplicated pregnancy to test the hypothesis of the existence of an association between volume-dependent echocardiographic parameters and Doppler ultrasound parameters of fetal circulation and the uterine artery in uncomplicated pregnancy and to establish which of the volume-dependent echocardiographic parameters best depicts volume changes and correlates best with Doppler ultrasound of fetal circulation and the uterine artery in healthy pregnancy. STUDY DESIGN: Data from 60 healthy pregnant women were analyzed. A complete echocardiographic study was performed at 11 to 13, 20 to 22, and 30 to 32 weeks' gestation: left ventricular end-diastolic volume, early diastolic peak flow velocity, late diastolic peak flow velocity, left atrial area, and left atrial volume index were assessed. Obstetrical assessment was performed including fetal growth and uterine artery pulsatility index. Fetal well-being was assessed by umbilical and middle cerebral artery blood flow. Serum pregnancy-associated plasma protein A and free ß-human chorionic gonadotropin were assessed during the routine first-trimester scan (11-13 weeks' gestation). RESULTS: Left ventricular end-diastolic volume and left atrial area increased significantly between 11 to 13 and 20 to 22 weeks' gestation but not between 20 to 22 and 30 to 32 weeks' gestation. Left atrial volume index measured at 30 to 32 weeks' gestation correlated with uterine artery pulsatility indices in 3 trimesters. Changes in the left atrial volume index between the third and first trimesters correlated significantly with the uterine artery pulsatility index measured at 20 to 22 weeks' gestation (r=-0.345; P=.020) and at 30 to 32 weeks' gestation (r=-0.452; P=.002). Changes in the left atrial volume index between the second and first trimesters significantly correlated with the uterine artery pulsatility index measured in the first trimester (r=-0.316; P=.025). CONCLUSION: Our study showed that in an uncomplicated pregnancy, among volume-dependent echocardiographic parameters, left atrial volume index increased between both the first and second trimesters and the second and third trimesters and correlated with parameters of Doppler ultrasound of the fetal circulation and the uterine artery. Our results expand on the previous observation on the relationship between maternal cardiovascular adaptation and placentation in women with heart diseases to the population of healthy women with uncomplicated pregnancy.

Evaluation of liver fibrosis in patients with Wilson's disease.

OBJECTIVES: Staging of fibrosis in chronic liver disease is important for prognosis and treatment planning. Liver biopsy is the gold standard in fibrosis assessment; however, new methods for fibrosis and stiffness measurement exist which have not been evaluated in patients with Wilson's disease. To evaluate the accuracy of collagen proportionate area (CPA), transient elastography and shear wave elastography (SWE) in the assessment of liver fibrosis in adult patients with Wilson's disease. METHODS: In this retrospective study of 60 patients with Wilson's disease, results of percutaneous cutting liver biopsy assessed using the Ishak fibrosis score and CPA were compared with liver stiffness measured with transient elastography and SWE. RESULTS: CPA correlated with the Ishak score (r = 0.45; P = 0.001) and transient elastography results correlated with SWE measurements (r = 0.80; P = 0.0001). In contrast, transient elastography or SWE did not significantly correlate with the Ishak score or CPA. CONCLUSION: Collagen content assessment may be useful for estimation of liver fibrosis in patients with Wilson's disease. However, single time-point elastographic liver stiffness measurements have a limited diagnostic value in Wilson's disease.

Primary aldosteronism is highly prevalent in patients with hypertension and moderate to severe obstructive sleep apnea.

STUDY OBJECTIVES: It has been suggested that there might be a pathophysiological link and overlap between primary aldosteronism (PA) and obstructive sleep apnea (OSA). Therefore, in a prospective study, we evaluated the frequency of PA in hypertensive patients suspected of having OSA. METHODS: We included 207 consecutive hypertensive patients (mean age 53.2 ± 12.1 years, 133 M, 74 F) referred for polysomnography on the basis of one or more of the following clinical features: typical OSA symptoms, resistant or difficult-to-treat hypertension, diabetes, or cardiovascular disease. PA was diagnosed based on thew saline infusion test. RESULTS: Moderate-to-severe OSA was diagnosed in 94 patients (45.4% of the whole group). PA was diagnosed in 20 patients with OSA (21.3%) compared with 9 patients in the group without OSA (8.0%; P = .006). PA was also frequent in patients in whom symptoms of OSA were a sole indication for PA screening (15.4%) and in patients with and without resistant hypertension (24.5% and 17.8%, respectively). Most patients with PA and OSA were diagnosed with bilateral adrenal hyperplasia (18 patients, 90%). There were no major differences in clinical characteristics between patients with OSA with PA and those without PA. In multivariate models, moderate-to-severe OSA predicted the presence of PA (odds ratio 2.89, P = .018). CONCLUSIONS: Patients with clinically important moderate-to-severe OSA are characterized by a relatively high frequency of PA. Our results support the recommendations to screen patients with moderate-to-severe OSA for PA, regardless of the presence of other indications for PA screening.

Left Ventricular Structural and Functional Alterations in Patients With Pheochromocytoma/Paraganglioma Before and After Surgery.

OBJECTIVES: This study sought to evaluate left ventricular (LV) structure and function in pheochromocytoma and paraganglioma (PPGL) patients before and after curative surgery. BACKGROUND: Data on catecholamine-induced effects on LV structure and function in patients with PPGL are limited and conflicting. METHODS: The study evaluated 81 consecutive patients with a PPGL, among whom 66 were evaluated 12 months after tumor removal. Fifty patients matched for age, sex, hypertension presence, and blood pressure (BP) levels served as a control group (non-PPGL group). Echocardiography was employed to assess the LV mass index (LVMI), systolic function including speckle tracking echocardiography, and diastolic function. RESULTS: Patients with PPGL were characterized by higher LVMI (median 103 [interquartile range (IQR): 88 to 132] g/m2 vs. median 94 [IQR: 74 to 106] g/m2; p = 0.006) and frequency of LV hypertrophy (44.4% vs. 24.0%; p = 0.018) compared with the non-PPGL group. Patients with PPGLs were characterized by lower global longitudinal strain (GLS) and early diastolic mitral annular velocity compared with patients in the non-PPGL group (median -17.2% [IQR: 15.6% to 18.9%] vs. median -19.3% [IQR: 17.7% to 20.6%]; p < 0.001; and median 11.1 [IQR: 8.3 to 13.0] cm/s vs. median 12.3 [IQR: 10.6 to 14.6] cm/s; p = 0.018, respectively). Presence of LV hypertrophy and GLS were independently associated with plasma free metanephrine concentrations. In operated patients, there were lower frequencies of LV hypertrophy (39.4% vs. 22.7%; p = 0.003), LVMI (median 98 [IQR: 85 to 115] g/m2 vs. median 90 [IQR: 76 to 109] g/m2; p < 0.001), and the ratio of transmitral early diastolic velocity to early diastolic mitral annular velocity (median 6.8 [IQR: 5.5 to 8.6] vs. median 6.0 [IQR: 5.0 to 7.6]; p = 0.005) but higher values for GLS (median -17.4 [IQR: -15.8 to 19.1] vs. median -18.5 [IQR: -17.1 to 20.1] p < 0.001) after compared with before surgery. CONCLUSIONS: Catecholamine excess in patients with PPGLs can lead not only to LV hypertrophy, but also to impairment of systolic LV function and subclinical alterations of diastolic LV function, independently of BP levels. These structural and functional changes are reversible after surgical intervention.

Blood pressure profile, sympathetic nervous system activity, and subclinical target organ damage in patients with polycythemia vera.

INTRODUCTION: Polycythemia vera (PV) is a rare myeloproliferative disease associated with an increased prevalence of hypertension and increased risk of cardiovascular complications. However, the precise mechanisms leading to the elevation of blood pressure (BP) and secondary target organ damage remain poorly understood. OBJECTIVES: The study aimed to evaluate BP profile, assess the activity of the sympathetic nervous system and the renin­angiotensin system, and provide a comprehensive assessment of subclinical target organ damage in patients with PV. PATIENTS AND METHODS: Twenty consecutive patients with newly diagnosed PV and 20 control subjects were included. The following were assessed: BP, levels of catecholamines, urinary and plasma O­methylated catecholamine metabolites, concentrations of aldosterone and renin. We also assessed microneurography sympathetic nervous system activity (MSNA) and baroreflex control of heart rate as well as subclinical target organ damage. RESULTS: At similar levels of BP, BP variability was decreased in the PV group (mean [SD] 24­hour systolic BP, 9 [3] vs 12 [3] mm Hg; P = 0.003). Patients with PV had lower norepinephrine excretion (mean [SD], 16.54 [6.32] vs 25.46 [12.88] µg/d; P = 0.03) as well as decreased MSNA as assessed by microneurography compared with controls (mean [SD] MSNA, 30.7 [8.7] bursts/min vs 38.7 [5.4] bursts/min; P = 0.007 and MSNA 51.8 [11] bursts/100 beats vs 61.1 [11.3] bursts/100 heart beats; P = 0.04). Baroreflex control of HR was unaltered in the PV group. Increased hemoglobin levels and red blood cell count correlated with decreased retinal capillary flow in patients with PV. CONCLUSIONS: Patients with PV, characterized by high hemoglobin concentrations and hematocrit levels had lower sympathetic nervous activity and decreased BP variability as compared with controls. There was no relationship between hemoglobin plasma concentration, hematocrit level, and target organ damage.