Low density lipoprotein particles are small in patients with coronary vasospasm

Management of Patients with Type V Hyperlipoproteinemia: An Uncommon Phenotype of Dyslipidemia with Chylomicronemia and Severe Hypertriglyceridemia

Hypertriglyceridemia (HTG) remains a risk-enhancing factor of atherosclerotic cardiovascular disease. We aimed to report real-world data on the management of patients with type V hyperlipoproteinemia (HLP5), an uncommon phenotype of dyslipidemia characterized by fasting chylomicronemia and severe HTG. Between July 2018 and May 2021, 90 patients with HTG, including 83 patients with type IV hyperlipoproteinemia (HLP4) and 7 patients with HLP5, were identified by plasma apolipoprotein B (apoB) and lipoprotein electrophoresis. Patients with HLP5 were younger, had higher total cholesterol (TC) (264.9 ± 26.7 mg/dL vs. 183.9 ± 26.1 mg/dL; p < 0.01) and higher triglyceride (TG) (1296.7 ± 380.5 mg/dL vs. 247.6 ± 96.1 mg/dL; p < 0.01), and had lower high-density lipoprotein cholesterol (HDL-C) (30.6 ± 4.8 mg/dL vs. 40.5 ± 8.7 mg/dL; p < 0.01) and lower low-density lipoprotein cholesterol (LDL-C) (62.9 ± 16.4 vs. 103.0 ± 21.1 mg/dL; p < 0.01) compared with patients with HLP4. Despite an aggressive use of statin and fenofibrate with greater reductions in TG (-65.9 ± 13.7% vs. -27.9 ± 30.5%; p < 0.01) following 6 months of treatment, patients with HLP5 had persistent HTG (440.1 ± 239.0 mg/dL vs. 173.9 ± 94.8 mg/dL; p < 0.01) and an increase in LDL-C (28.3 ± 57.2% vs. -19.5 ± 32.0%; p < 0.01) compared with patients with HLP4. Our findings highlight that the lack of novel TG-lowering medications and management guidelines remains an unmet medical need in patients with HLP5. Closely monitoring lipid profiles, full assessment of individual’s risk of cardiovascular disease, and emphasis on medication adherence are of clinical importance.

Pathobiology and evolving therapies of coronary artery vasospasm

Coronary artery vasospasm is a known cause of chest pain and requires a high level of clinical suspicion for diagnosis. It also remains in the differential diagnosis for patients presenting with type 2 myocardial infarction. There are few randomized controlled trials for guideline-based prevention and treatment for coronary artery vasospasm. In this article, we review updated concepts in coronary artery vasospasm. Specifically, our aim is to provide current evidence of pathophysiology, identify the risk factors, propose a diagnostic algorithm, review available evidence of evolving therapies, and identify patients who would benefit from automatic implantable cardioverter defibrillators.

Low-density-lipoprotein particle size predicts a poor outcome in patients with atherothrombotic stroke

BACKGROUND AND PURPOSE

Low-density lipoprotein (LDL) particle size is considered to be one of the more important cardiovascular risk factors, and small LDL particles are known to have atherogenic potential. The aim of this study was to determine whether LDL particle size is associated with stroke severity and functional outcome in patients with atherothrombotic stroke.

METHODS

Between January 2009 and May 2011, 248 patients with first-episode cerebral infarction who were admitted to our hospital within 7 days after symptom onset were prospectively enrolled. LDL particle size was measured using the nondenaturing polyacrylamide gradient gel electrophoresis assay. Stroke severity was assessed by applying the National Institutes of Health Stroke Scale (NIHSS) at admission. Functional outcome was investigated at 3 months after the index stroke using the modified Rankin Scale (mRS), and poor functional outcome was defined as an mRS score of ≥3.

RESULTS

The LDL particle size in the 248 patients was 25.9±0.9 nm (mean±SD). LDL particle size was inversely correlated with the degree of cerebral artery stenosis (p=0.010). Multinomial multivariate logistic analysis revealed that after adjustment for age, sex, and variables with p<0.1 in univariate analysis, LDL particle size was independently and inversely associated with stroke severity (NIHSS score ≥5; reference, NIHSS score 0-2; odds ratio=0.38, p=0.028) and poor functional outcome (odds ratio=0.44, p=0.038).

CONCLUSIONS

The results of this study demonstrate that small LDL particles are independently correlated with stroke outcomes. LDL particle size is thus a potential biomarker for the prognosis of atherothrombotic stroke.

LDL cholesterol as a novel risk factor for contrast-induced acute kidney injury in patients undergoing percutaneous coronary intervention

BACKGROUND

Low density lipoprotein cholesterol (LDL-C) is associated with endothelial dysfunction, inflammation and increased vasoconstriction, which are involved in the development of contrast-induced acute kidney injury (CI-AKI). However, whether LDL-C is an independent risk factor of CI-AKI in patients undergoing percutaneous coronary intervention (PCI) is unknown.

METHODS

We prospectively enrolled 3236 consecutive patients undergoing PCI between January 2010 and September 2012. Multivariate logistic regression analysis was used to determine whether LDL-C is an independent risk factor of CI-AKI. CI-AKI was defined as an absolute increase in serum creatinine of ≥ 0.5 mg/dL or ≥ 25% over the baseline value within 48-72 h after contrast exposure.

RESULTS

CI-AKI was observed in 338 patients (10.4%). Patients with CI-AKI had a significantly higher rate of in hospital mortality (4.4% vs. 0.5%, p < 0.001), and significantly higher rates of other in hospital complications compared with those without CI-AKI. The LDL-C quartiles were as follows: Q1 (<2.04 mmol/L), Q2 (2.04-2.61 mmol/L), Q3 (2.61-3.21 mmol/L) and Q4 (>3.21 mmol/L). Patients with high baseline LDL-C levels were more likely to develop CI-AKI and composite end points including all-cause mortality, renal replacement therapy, non-fatal myocardial infarction, acute heart failure, target vessel revascularization or cerebrovascular accident during the observation period of hospitalization (8.9%, 9.9%, 10.5%, 12.6%, p = 0.001, and 5.0%, 5.2%, 6.1%, 8.1%, respectively; p = 0.007). Univariate logistic analysis showed that LDL-C levels (increment 1 mmol/L) were significantly associated with CI-AKI (odds ratio = 1.25, 95% confidence interval (CI), 1.11-1.39, p < 0.001). Furthermore, LDL-C remained a significant risk factor of CI-AKI (odds ratio = 1.23, 95% CI, 1.04-1.45, p = 0.014), even after adjusting for potential confounding risk factors.

CONCLUSIONS

Measurement of plasma LDL-C concentrations in patients undergoing PCI may be helpful to identify those who are at risk of CI-AKI and poor in hospital outcomes.

Postpartum coronary vasospasm with literature review

Acute myocardial infarction during pregnancy or the postpartum period is rare. We report a case of a 39-year-old postpartum woman who developed non-ST-elevation myocardial infarction due to severe diffuse coronary vasospasm. To our knowledge, this is the first case of angiographically evidenced coronary vasospasm, in a postpartum woman, with resistance to intracoronary nitroglycerin.

Pioglitazone improves the cardio-ankle vascular index in patients with type 2 diabetes mellitus treated with metformin

BACKGROUND

Type 2 diabetes is known to be associated with elevated cardiovascular mortality. Pioglitazone improves blood pressure (BP) and pulse wave velocity (PWV), which is an arterial stiffness parameter. Arterial stiffness is closely associated with cardiovascular disease. However, PWV is correlated with BP. The cardio-ankle vascular index (CAVI) reflects arterial stiffness independent of BP. Pioglitazone improves PWV but reduces blood pressure. The aim of this study was to re-evaluate the effect of pioglitazone on arterial stiffness with CAVI.

METHODS

Sixty patients with type 2 diabetes mellitus and already on 500 mg/day of metformin received add-on therapy of pioglitazone 15 mg/day or glimepiride 1 mg/day for 6 months, during which time changes in their metabolic parameters and CAVI were observed.

RESULTS

After 6 months of treatment, both pioglitazone (n=30) and glimepiride (n=30) improved fasting blood glucose and glycated hemoglobin. The changes in fasting blood glucose and glycated hemoglobin between the two groups were greater in the pioglitazone group. Systolic and diastolic BP was decreased in both groups, with no significant between-group differences. Only pioglitazone increased serum adiponectin levels, and the change in adiponectin between the pioglitazone and glimepiride groups was significantly different. CAVI was decreased significantly by pioglitazone but remained unchanged after treatment with glimepiride. The change in CAVI between the two groups was significantly different.

CONCLUSION

These results suggest that pioglitazone improves CAVI, a BP-independent arterial stiffness parameter, in patients with type 2 diabetes mellitus treated with metformin.

Changes in small dense low-density lipoprotein levels following acute coronary syndrome

Low-density lipoprotein (LDL), especially small dense LDL (sdLDL), plays a role in atherogenesis. We compared baseline sdLDL levels between healthy controls and patients with acute coronary syndrome (ACS). Blood samples were taken from patients diagnosed with myocardial infarction ([MI] n = 104) and unstable angina ([UA] n = 100). Both sdLDL and high-sensitivity C-reactive protein (hsCRP) levels were determined on admission and in the next 24 hours after the onset of symptoms. Baseline concentration of sdLDL was significantly higher in patients presenting with ACS than controls (P < .05). In the 24 hours following ACS, the sdLDL levels decreased insignificantly in both groups of patients with ACS (P > .05). The changes in sdLDL values were not significantly different between MI and UA participants (P > .05). Patients with ACS have higher concentration of sdLDL compared with the controls.

Improvement of postprandial hyperglycemia and arterial stiffness upon switching from premixed human insulin 30/70 to biphasic insulin aspart 30/70

Postprandial hyperglycemia is known to be associated with increasing cardiovascular mortality in type 2 diabetes mellitus patients. Cardio-ankle vascular index (CAVI) reflects arterial stiffness and is more useful for predicting coronary atherosclerosis than intima-media thickness. Premixed human insulin 30/70 (BHI30) containing rapid-acting insulin has been used conventionally as a biphasic insulin. Recently, a biphasic insulin analogue preparation, biphasic insulin aspart 30/70 (BIAsp30), containing ultrarapid-acting insulin has been approved and expected to improve postprandial hyperglycemia. The aim of this study was to clarify the effects of switching the biphasic insulin from BHI30 to BIAsp30 on arterial stiffness in type 2 diabetes mellitus patients. Twenty-six type 2 diabetes mellitus patients (glycosylated hemoglobin >6.5%) who were already receiving biphasic insulin therapy with BHI30 twice daily were observed for 3 months. Afterward, BHI30 was switched to BIAsp30. At 3 months after switching, relative mobility of the peak of LDL fraction decreased significantly (from 0.3462 ± 0.041 to 0.3356 ± 0.035, P < .01); and CAVI also decreased significantly (from 9.77 ± 1.11 to 9.35 ± 1.17 m/s, P < .005). A significant negative correlation was observed between the change in CAVI and change in 1,5-anhydroglucitol (1,5-AG) (r = -0.3929, P < .05). A stronger correlation between change in CAVI and change in 1,5-AG was observed in the subgroup of patients whose 1,5-AG levels were elevated after switching (r = -0.6261, P < .05) compared with all subjects. These results suggest that switching biphasic insulin from BHI30 to BIAsp30 improves arterial stiffness, and the improvement of arterial stiffness may be associated with improvement of postprandial hyperglycemia.

Does simultaneous determination of LDL and HDL particle size improve prediction of coronary artery disease risk?

BACKGROUND

Alterations in plasma lipoprotein subclass distribution affect the risk for coronary artery disease (CAD). However, it is unclear whether the determination of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) phenotypes may or may not improve the ability to predict CAD development.

METHODS

Polyacrylamide gradient (3-31%) gel electrophoresis was used to simultaneously determine size and distribution of lipoprotein subclasses in 181 CAD patients and 178 controls.

RESULTS

Mean LDL and HDL subclass sizes were significantly smaller in patients than in controls (p < 0.001). Multivariate logistic regression analysis showed that small dense LDL particles were independent CAD risk predictors (OR = 2.867, p < 0.01), even when adjusted for other traditional risk factors, while small HDL particles lost their significance after adjustment (OR = 2.071, p = 0.054). The area under the ROC curve for LDL (0.671) and HDL (0.643) particle size measurement demonstrated low clinical accuracy when compared to the combination of traditional lipid risk factor measurements.

CONCLUSIONS

CAD is associated with the predominance of smaller LDL and HDL particles. However, simultaneous determination of these two lipoprotein phenotypes provides no additional power in discriminating CAD and non-CAD subjects, beyond that obtained by the traditional risk factors.

Effect of metformin on serum lipoprotein lipase mass levels and LDL particle size in type 2 diabetes mellitus patients

We previously reported that lipoprotein lipase mass levels in preheparin serum (preheparin LPL mass) was significantly lower in type 2 diabetes mellitus compared to healthy subjects and that low preheparin LPL mass may be a high-risk factor of coronary atherosclerosis. The aim of this study was to clarify the effects of metformin on serum lipoprotein lipase mass levels (preheparin LPL mass), adiponectin and lipid metabolism in patients with type 2 diabetes mellitus. Twenty-eight patients with type 2 diabetes mellitus (HbAlc>7.0%), who were already receiving sulfonylurea agents, took metformin 500 mg orally twice daily for 3 months. Fasting blood glucose (FBG), immunoreactive insulin (basal IRI) and HbAlc decreased significantly after metformin treatment. LDL-Rm ratio decreased significantly (from 0.3521+/-0.046 to 0.3339+/-0.030, P<0.05) and preheparin LPL mass increased significantly (from 42.5+/-3.2 to 50.6+/-3.5 ng/ml, P<0.0005), but adiponectin was unchanged. The correlation of a change of LDL-Rm ratio and a change of preheparin LPL mass showed a negative correlation tendency. The changes in LDL-Rm ratio and preheparin LPL mass were independent of the hypoglycemic effect of metformin. These results suggest that metformin may increase LPL production, thereby increasing LDL particle size. These effects might be independent of the hypoglycemic effect of metformin.

Small, dense low-density-lipoproteins and the metabolic syndrome

Small, dense low-density-lipoproteins (LDL) are associated with increased risk for cardiovascular diseases and diabetes mellitus and a reduction in LDL size has been reported in patients with coronary and non-coronary forms of atherosclerosis. LDL size has been accepted as an important predictor of cardiovascular events and progression of coronary artery disease as well as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. Small, dense LDL, with elevated triglyceride levels and low HDL-cholesterol concentrations, constitute the 'atherogenic lipoprotein phenotype (ALP)', a form of atherogenic dyslipidemia that is a feature of type 2 diabetes and the metabolic syndrome. LDL size and subclasses show specific alterations in patients with the metabolic syndrome that probably significantly increase their cardiovascular risk; however, so far it has not been recommended to incorporate LDL size measurements in treatment plans, when hypolipidemic therapies are installed. Patients with type 2 diabetes are at high cardiovascular risk and it is still on debate if the treatment goals may be identical or whether there are distinct groups with different cardiovascular risks and hence with different treatment goals. Measurements beyond traditional lipids, such as measurements on the presence of small, dense LDL in patients with the metabolic syndrome, may help to identify cardiovascular risk subgroups. In addition, it might be possible in the future to individualize hypolipidemic treatments if more than the traditional lipids are taken into account. LDL size measurement may potentially help to assess cardiovascular risk within the metabolic syndrome and adapt the treatment goals thereafter.

Clinical importance and therapeutic modulation of small dense low-density lipoprotein particles

The National Cholesterol Education Programme Adult Treatment Panel III accepted the predominance of small dense low-density lipoprotein (sdLDL) as an emerging cardiovascular disease (CVD) risk factor. Most studies suggest that measuring low-density lipoprotein (LDL) particle size, sdLDL cholesterol content and LDL particle number provides additional assessment of CVD risk. Therapeutic modulation of small LDL size, number and distribution may decrease CVD risk; however, no definitive causal relationship is established, probably due to the close association between sdLDL and triglycerides and other risk factors (e.g., high-density lipoprotein, insulin resistance and diabetes). This review addresses the formation and measurement of sdLDL, as well as the relationship between sdLDL particles and CVD. The effect of hypolipidaemic (statins, fibrates and ezetimibe) and hypoglycaemic (glitazones) agents on LDL size and distribution is also discussed.

Should we measure routinely the LDL peak particle size?

Low density lipoproteins (LDL) do not show in humans a normal distribution and comprise two different main fractions: large, buoyant (phenotype pattern A) and small, dense (phenotype pattern B) particles, that differ not only in size and density but also in physicochemical composition, metabolic behaviour and atherogenicity. The prevalence of small, dense LDL changes with age (30-35% in adult men, 5-10% in men <20 years and in pre-menopausal women, 15-25% in postmenopausal women) and is genetically influenced, with a heritability ranging from 35% to 45%. Small, dense LDL correlate negatively with plasma HDL levels and positively with plasma triglyceride levels and are associated with the metabolic syndrome and with increased risk for cardiovascular disease and diabetes mellitus. LDL size seems also to be an important predictor of cardiovascular events and progression of coronary artery disease and the predominance of small dense LDL has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. In addition, patients with acute myocardial infarction show an early reduction of LDL size, which persists during hospitalization and seems to precede all other plasma lipoprotein modifications. However, it is still on debate whether to measure the LDL size routinely and in which categories of patients. Since the therapeutic modulation of small, dense LDL particles is of great benefit in reducing the atherosclerotic risk, the LDL size measurement should be extended to patients at high risk of coronary artery disease as much as possible.

Low-density lipoprotein size and cardiovascular prevention

Low-density lipoprotein (LDL) size appears to be an important predictor of cardiovascular events and progression of coronary artery disease, and the predominance of small, dense LDL has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. Yet, other authors have suggested that LDL subclass measurement does not add independent information to that conferred generically by LDL concentration and other standard risk factors. Therefore, the debate continues as to whether to measure LDL particle size for cardiovascular prevention and, if so, in which categories of patients. Since the therapeutic modulation of distinct LDL subspecies is of great benefit in reducing the risk of cardiovascular events, LDL size measurement should be extended as much as possible to patients at high risk of cardiovascular diseases.

Low-density lipoprotein size and cardiovascular risk assessment

A predominance of small, dense low-density lipoproteins (LDL) has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease and evidences suggests that both quality (particularly small, dense LDL) and quantity may increase cardiovascular risk. However, other authors have suggested that LDL size measurement does not add information beyond that obtained by measuring LDL concentration, triglyceride levels and HDL concentrations. Therefore, it remains debatable whether to measure LDL particle size in cardiovascular risk assessment and, if so, in which categories of patient. Therapeutic modulation of LDL particle size or number appears beneficial in reducing the risk of cardiovascular events, but no clear causal relationship has been shown, because of confounding factors, including lipid and non-lipid variables. Studies are needed to investigate the clinical significance of LDL size measurements in patients with coronary and non-coronary forms of atherosclerosis; in particular, to test whether LDL size is associated with even higher vascular risk, and whether LDL size modification may contribute to secondary prevention in such patients.

Diffuse three-vessel coronary artery spasm

A 50-year-old woman came to the hospital because of chest pain, mostly occurring in the early morning at rest. She performed an exercise test on Bruce protocol and exercised up to 11 min (13 METs) without chest pain. Following ergonovine provocation test, diffuse three-vessel coronary artery spasm was identified.