Relating Lipoprotein(a) Concentrations to Cardiovascular Event Risk After Acute Coronary Syndrome: A Comparison of 3 Tests.

BACKGROUND: Lipoprotein(a) is a risk factor for cardiovascular events and modifies the benefit of PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitors. Lipoprotein(a) concentration can be measured with immunoassays reporting mass or molar concentration or a reference measurement system using mass spectrometry. Whether the relationships between lipoprotein(a) concentrations and cardiovascular events in a high-risk cohort differ across lipoprotein(a) methods is unknown. We compared the prognostic and predictive value of these types of lipoprotein(a) tests for major adverse cardiovascular events (MACE). METHODS: The ODYSSEY OUTCOMES trial (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) compared the PCSK9 inhibitor alirocumab with placebo in patients with recent acute coronary syndrome. We compared risk of a MACE in the placebo group and MACE risk reduction with alirocumab according to baseline lipoprotein(a) concentration measured by Siemens N-latex nephelometric immunoassay (IA-mass; mg/dL), Roche Tina-Quant turbidimetric immunoassay (IA-molar; nmol/L), and a noncommercial mass spectrometry-based test (MS; nmol/L). Lipoprotein(a) values were transformed into percentiles for comparative modeling. Natural cubic splines estimated continuous relationships between baseline lipoprotein(a) and outcomes in each treatment group. Event rates were also determined across baseline lipoprotein(a) quartiles defined by each assay. RESULTS: Among 11 970 trial participants with results from all 3 tests, baseline median (Q1, Q3) lipoprotein(a) concentrations were 21.8 (6.9, 60.0) mg/dL, 45.0 (13.2, 153.8) nmol/L, and 42.2 (14.3, 143.1) nmol/L for IA-mass, IA-molar, and MS, respectively. The strongest correlation was between IA-molar and MS (r=0.990), with nominally weaker correlations between IA-mass and MS (r=0.967) and IA-mass and IA-molar (r=0.972). Relationships of lipoprotein(a) with MACE risk in the placebo group were nearly identical with each test, with estimated cumulative incidences differing by ≤0.4% across lipoprotein(a) percentiles, and all were incrementally prognostic after accounting for low-density lipoprotein cholesterol levels (all spline P≤0.0003). Predicted alirocumab treatment effects were also nearly identical for each of the 3 tests, with estimated treatment hazard ratios differing by ≤0.07 between tests across percentiles and nominally less relative risk reduction by alirocumab at lower percentiles for all 3 tests. Absolute risk reduction with alirocumab increased with increasing lipoprotein(a) measured by each test, with significant linear trends across quartiles. CONCLUSIONS: In patients with recent acute coronary syndrome, 3 lipoprotein(a) tests were similarly prognostic for MACE in the placebo group and predictive of MACE reductions with alirocumab at the cohort level. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01663402.

Prognostic value of a low post-exercise ankle brachial index as assessed by primary care physicians.

OBJECTIVE: We aimed to investigate whether the post-exercise ankle brachial index (ABI) performed by primary care physicians offers useful information for the prediction of death or cardiovascular events, beyond the traditional resting ABI. An additional focus was on patients with intermittent claudication and normal resting ABI. METHODS: Using data from the 5-year follow-up of 6468 elderly patients in the primary care setting in Germany (getABI study) we used multivariate Cox regression models adjusted for age, gender and conventional risk factors to determine the association of resting ABI and/or post-exercise ABI and all-cause mortality/morbidity. RESULTS: Mean post-exercise ABI in the total cohort was 0.977 and resting ABI was 1.034. For post-exercise ABI, a threshold value of 0.825 had nearly the same sensitivity (28.6%) and specificity (85.7%) as the conventionally used resting ABI with a cut-off value of 0.9 to predict death. Compared to patients with normal post-exercise ABI, a low post-exercise ABI was associated with an almost identical risk increase for mortality (hazard ratio [HR] 1.56, 95% confidence interval [CI] 1.30-1.86) as a low resting ABI (HR 1.65; CI 1.39-1.97) and/or myocardial infarction/stroke. Slight differences were observed for coronary/carotid revascularisation and peripheral revascularisation/amputation. In combined models it could not be shown that post-exercise ABI yielded relevant additional information for the prognosis of mortality and/or myocardial infarction/stroke, not even in the subgroup analysis of patients with intermittent claudication and normal resting ABI. CONCLUSIONS: It could not be shown that the post-exercise ABI is a useful tool for the prognosis of mortality and/or myocardial infarction/stroke beyond the resting ABI.

Peripheral arterial disease as an independent predictor for excess stroke morbidity and mortality in primary-care patients: 5-year results of the getABI study.

BACKGROUND: There is controversial evidence with regard to the significance of peripheral arterial disease (PAD) as an indicator for future stroke risk. We aimed to quantify the risk increase for mortality and morbidity associated with PAD. METHODS: In an open, prospective, noninterventional cohort study in the primary care setting, a total of 6,880 unselected patients > or =65 years were categorized according to the presence or absence of PAD and followed up for vascular events or deaths over 5 years. PAD was defined as ankle-brachial index (ABI) <0.9 or history of previous peripheral revascularization and/or limb amputation and/or intermittent claudication. Associations between known cardiovascular risk factors including PAD and cerebrovascular mortality/events were analyzed in a multivariate Cox regression model. RESULTS: During the 5-year follow-up [29,915 patient-years (PY)], 183 patients had a stroke (incidence per 1,000 PY: 6.1 cases). In patients with PAD (n = 1,429) compared to those without PAD (n = 5,392), the incidence of all stroke types standardized per 1,000 PY, with the exception of hemorrhagic stroke, was about doubled (for fatal stroke tripled). The corresponding adjusted hazard ratios were 1.6 (95% confidence interval, CI, 1.1-2.2) for total stroke, 1.7 (95% CI 1.2-2.5) for ischemic stroke, 0.7 (95% CI 0.2-2.2) for hemorrhagic stroke, 2.5 (95% CI 1.2-5.2) for fatal stroke and 1.4 (95% CI 0.9-2.1) for nonfatal stroke. Lower ABI categories were associated with higher stroke rates. Besides high age, previous stroke and diabetes mellitus, PAD was a significant independent predictor for ischemic stroke. CONCLUSIONS: The risk of stroke is substantially increased in PAD patients, and PAD is a strong independent predictor for stroke.

Significance of initial blood pressure and comorbidity for the efficacy of a fixed combination of an angiotensin receptor blocker and hydrochlorothiazide in clinical practice.

BACKGROUND: Two-thirds of all patients with arterial hypertension need drug combinations to achieve blood pressure (BP) goals. Fixed combinations have high efficacy and result in high patient compliance. 300 mg irbesartan plus 25 mg hydrochlorothiazide (HCTZ) has been investigated only in clinical trials but not in daily practice. METHODS: A multicenter, noninterventional, noncontrolled observational study with 8123 patients seen by 1604 physicians in daily practice. BP reduction (office measurements), co-morbid disease and tolerability were documented over a 6-month observational period. RESULTS: At mean baseline BP of 161 +/- 15/94 +/- 10 mmHg, administering of fixed combination resulted in a substantial BP reduction averaging 28 +/- 15/14 +/- 10 mmHg (P < 0.001). Decrease of systolic BP ran parallel with increasing systolic baseline BP (Spearman's Rho -0.731; P < 0.0001; diastolic BP vs diastolic baseline BP Rho 0.740; P < 0.0001), independent from patient characteristics (age, obesity, diabetes or nephropathy) but enhanced with short history of hypertension (P < 0.0001 vs long history), prior beta blockers (P = 0.001 vs prior angiotensin receptor blockers [ARBs]), prior calcium channel blockers (P = 0.046 vs prior ARBs) and no prior medication (P = 0.012 vs prior ARBs). High compliance (>98%) and low incidence of adverse events (0.66%) were documented. CONCLUSIONS: The fixed combination of 300 mg irbesartan with 25 mg HCTZ was efficacious and tolerable in an unselected patient population in primary care.

Risk factor profile, management and prognosis of patients with peripheral arterial disease with or without coronary artery disease: results of the prospective German REACH registry cohort.

AIMS: Peripheral arterial disease (PAD) and coronary artery disease (CAD) are manifestations of the same underlying condition, atherothrombosis. We compared patients with PAD only with those having PAD and concomitant documented CAD in terms of characteristics, risk factors, treatment and prognosis. METHODS AND RESULTS: This is a subgroup analysis of the German cohort of the Reduction of Atherothrombosis for Continued Health (REACH) Registry. It includes 483 patients with PAD only, and 479 patients with PAD plus CAD. Patients with concomitant cerebrovascular disease were excluded. Symptomatic PAD was defined as intermittent claudication (IC), confirmed by ankle brachial index <0.9, or PAD-related intervention. Patients in the total cohort were predominantly elderly (mean age 67.3 +/- 8.9 years), males (72.3%), current or previous smokers (80.18%), and had often abdominal obesity (49.6%). Atherosclerotic risk factors and comorbidities were highly prevalent. Patients with PAD + CAD compared to those with PAD only were significantly more intensively treated with regards to antihrombotic agents (97.1% vs. 88.8%), statins (80.2% vs. 51.6%), or ACE inhibitors/ARB (75.6% vs. 61.1%). After two-year follow-up, no significant differences between subgroups were noted for total mortality (4.6% vs. 5.5%), cardiovascular mortality (3.7% vs. 3.9%), non-fatal myocardial infarction (1.9% vs. 2.7%) but for non-fatal stroke (4.4% vs. 2.0%, P < 0.05). CONCLUSION: Peripheral arterial disease patients carry a high burden of risk factors and co-morbidities, and are at high risk of death and cardiovascular events. If documented CAD is absent, PAD patients are undertreated. Thus, in PAD patients, secondary cardiovascular prevention with stringent treatment of risk factors to the same extent as in CAD patients is mandatory, in line with current guidelines.

Determination of renal porphyrin handling in rats suffering from different kinds of chronic renal failure (CRF): uranyl nitrate (UN) induced fibrosis or 5/6-nephrectomy (5/6NX).

The renal handling of porphyrins is reported to be a sensitive marker for chronic renal failure (CRF) for two reasons: heme is synthesised in proximal tubules and porphyrins are reabsorbed in the renal proximal tubule by apical peptide transporter PEPT 2. Two different models of CRF in female Wistar rats have been used for investigation of renal porphyrin handling: (1) single administration of uranyl nitrate (UN; 0.5 mg/100 g b.wt.) and (2) 5/6 nephrectomy (5/6NX). Renal clearance experiments were performed at weeks 2 and 10 after the onset of CRF. The concentrations of porphyrin intermediates (uroporphyrin I and III, coproporphyrin I and II, heptaporphyrin, and pentaporphyrin) were measured by HPLC with fluorescence detection. Both after UN and 5/6NX a significant reduction of body weight occurred. The kidney weight was enhanced 2 weeks after UN compared to controls (+31%). After 5/6NX, the weight of the remnant kidney was 44% (2nd week) and 140% (10th week) higher compared to one control kidney. Urine volumes and GFR were significantly reduced at week 2 and 10 after 5/6NX, but at week 10 after UN values were comparable to controls. Two weeks after UN and 5/6NX the concentrations of heptaporphyrin was moderately decreased in renal tissue whereas after 10 weeks the concentrations of most porphyrins were increased in the kidney. The plasma levels of free porphyrins were only slightly enhanced (week 2). The renal excretion of porphyrins was initially slightly reduced in both models, whereas it increases 10 weeks after UN, but it remained reduced 10 weeks after 5/6NX. UN induces tubulointerstitial fibrosis including atrophic glomeruli, whereas 5/6NX was characterized by distinct proteinuria, dilated tubules containing hyaline casts. A modulation of porphyrin metabolism in the kidney seems first of all to be responsible for UN effect on renal porphyrin handling. Summing up the 5/6NX results, both reduction in intact renal tissue mass and a modification of enzymes involved in heme biosynthesis by uraemic toxins are responsible for accumulation of porphyrins in renal tissue. After 5/6NX reduced excretion of porphyrins into urine and enhanced porphyrin concentrations in the kidney indicate more a damage of renal porphyrin biosynthesis than changes in their reabsorption.