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Eric Boersma

Publications and source records attributed to Eric Boersma.

At least 145 records · Page 8Linked to original sources
PubMed2003

Feasibility and image quality of dual-isotope SPECT using 18F-FDG and (99m)Tc-tetrofosmin after acipimox administration.

UNLABELLED: Currently, with the rapidly increasing number of patients with heart failure due to chronic coronary artery disease, the need for viability studies to guide treatment in these patients is increasing. The most accurate method for viability assessment is metabolic imaging with (18)F-FDG with PET or SPECT. To obtain excellent image quality in all patients, the (18)F-FDG studies should be performed during hyperinsulinemic euglycemic clamping. However, this approach is time-consuming and is not feasible in busy nuclear medicine laboratories. Recently, the use of a nicotinic acid derivative, acipimox, has been suggested, but limited data are available on the image quality of the (18)F-FDG studies using this approach. METHODS: We evaluated the feasibility and image quality of (18)F-FDG SPECT (with dual-isotope simultaneous acquisition (DISA) using (99m)Tc-tetrofosmin to assess perfusion) after acipimox administration in 50 nondiabetic patients. The image quality of both (18)F-FDG and (99m)Tc-tetrofosmin was assessed visually and quantitatively using myocardium-to-blood-pool (M/B) ratios as a measure of target-to-background ratio. The image quality and diagnostic value of DISA (99m)Tc-tetrofosmin SPECT was compared with standard (99m)Tc-tetrofosmin SPECT at baseline. RESULTS: After acipimox administration, the plasma levels of free fatty acids were extremely low (68 +/- 89 nmol/L). No severe side effects were observed, only paroxysmal flushing. The (18)F-FDG image quality was good in 46 patients (92%) and moderate but still interpretable in the other 4 patients (8%). The clinical information of the baseline (99m)Tc-tetrofosmin SPECT was retained in the DISA (99m)Tc-tetrofosmin SPECT images because we did observe no substantial fill-in of perfusion defects by high (18)F-FDG uptake in the same segment. CONCLUSION: Cardiac (18)F-FDG SPECT after acipimox is safe and resulted consistently in good image quality; this simple approach may be the method of choice for routine cardiac metabolic imaging.

Administration, Oral↗
PubMed2003

Sensitivity and specificity of QCA in detecting coronary arterial remodeling after intracoronary brachytherapy: a comparison to serial volumetric three-dimensional intravascular ultrasound analysis. Can we detect positive remodeling by luminography?

BACKGROUND: After treatment with intracoronary brachytherapy, enlargement of lumen (negative late loss) at follow-up has been demonstrated. The aim of the study is to analyze the sensitivity and specificity of quantitative coronary angiography (QCA) parameters to detect a positive vessel remodeling after intracoronary -radiation as compared to intravascular ultrasound (IVUS). METHODS: Twenty-seven patients (27 vessels) treated with balloon angioplasty followed by catheter-based intracoronary -radiation with a (90)Strontium/(90)Yttrium source were assessed by both QCA and three-dimensional IVUS with electrocardiogram-gated pullback. Irradiated segments were analyzed over the total treatment length and in subsegment lengths of 5 mm. RESULTS: Change in minimum luminal diameter (MLD) was not a predictor for the positive remodeling in either total irradiated segments or 5 mm subsegments, with a 54.3% ROC curve area [95% confidence interval (CI), 30-79%], sensitivity of 39% and specificity of 44% (p = not significant) in the total irradiated segments and a 55.9% ROC curve area (95% CI, 46-66%), sensitivity of 55% and specificity of 54% (p = not significant) in the 5 mm subsegments. Changes in mean and maximal lumen diameter were not significant parameters to detect positive vessel remodeling. When only central subsegments were analyzed, change in MLD was a significant predictor, with a 63.3% ROC curve area (95% CI, 52-75%), sensitivity of 55% and specificity of 64% (p = 0.029). CONCLUSION: Lumen enlargement detected by QCA does not reliably indicate a positive vessel remodeling after intracoronary radiation. IVUS analysis may be necessary to investigate the mechanism of restenosis after balloon angioplasty followed by catheter-based radiation.

Angioplasty, Balloon, Coronary↗
PubMed2002

Perfusion and contractile reserve in chronic dysfunctional myocardium: relation to functional outcome after surgical revascularization.

BACKGROUND: Chronic dysfunctional but viable myocardium may exhibit contractile reserve and/or intact perfusion. Segments with intact perfusion without contractile reserve are frequently observed inpatients with ischemic cardiomyopathy. The clinical relevance of this observation is unclear; in particular, the functional outcome after revascularization is unknown. Thus, contractile reserve (using low-dose dobutamine echocardiography) and perfusion (using resting (99m)Tc tetrofosmin) were evaluated in 114 patients with ischemic cardiomyopathy and the findings were related to functional outcome (9 to 12 months after revascularization). METHODS AND RESULTS: Patients (n=114) with ischemic cardiomyopathy undergoing surgical revascularization were evaluated for perfusion (using (99m)Tc tetrofosmin) and contractile reserve (using low-dose dobutamine echocardiography). Contractile function (two-dimensional echocardiography) was assessed before and 9 to 12 months after revascularization. In the 1 336 dysfunctional segments, perfusion was preserved in 51% of the segments and contractile reserve in 31% (P<.05); 47% of the segments with perfusion did not exhibit contractile reserve. The majority (66%) of segments with recovery of function postrevascularization had intact perfusion and contractile reserve; the majority (58%) of segments without functional recovery lacked both perfusion and contractile reserve. Interestingly, 22% of segments with functional recovery and 25% of segments without functional recovery showed intact perfusion without contractile reserve. CONCLUSION: Segments with intact perfusion/contractile reserve have a high likelihood of recovery of function postrevascularization; segments without contractile reserve/perfusion have a low likelihood of recovery and segments with intact perfusion without contractile reserve have an intermediate likelihood of recovery.

Angina Pectoris↗
PubMed2002

Effectiveness of resynchronization therapy in patients with end-stage heart failure.

Biventricular pacing has been introduced to treat patients with end-stage heart failure, and short-term results of this technique are promising. Because data on longer follow-up are limited to 3-month follow-up, the sustained effect of biventricular pacing is unclear and long-term survival is unknown. Forty patients with end-stage heart failure in New York Heart Association (NYHA) functional class III or IV with left ventricular (LV) ejection fraction (EF) <35%, QRS duration >120 ms, and left bundle branch block morphology received a biventricular pacemaker. At baseline, and at 3 and 6 months after implantation, the following parameters were evaluated: NYHA class, Minnesota quality-of-life score, QRS duration on surface electrocardiogram, 6-minute walking distance, and LVEF. Long-term follow-up was obtained for up to 2 years. All clinical parameters improved significantly at 3 months and remained unchanged at 6-month follow-up. LVEF increased from 24 +/- 9% to 34 +/- 11%. Before implantation, patients were hospitalized (for congestive heart failure) an average of 3.9 +/- 5.3 days/year compared with 0.5 +/- 1.5 days/year after implantation. Long-term follow-up showed a survival of 87.5% at 2 years. Thus, biventricular pacing resulted in improvement of symptoms and quality of life, accompanied by improvement in 6-minute walking distance and LVEF. These effects were observed at 3 months after implantation and were maintained at 6-month follow-up. Moreover, 2-year survival was excellent.

Cardiac Pacing, Artificial↗
PubMed2002

Early angioplasty in acute coronary syndromes without persistent ST-segment elevation improves outcome but increases the need for six-month repeat revascularization: an analysis of the PURSUIT Trial. Platelet glycoprotein IIB/IIIA in Unstable angina: Receptor Suppression Using Integrilin Therapy.

OBJECTIVES: We explored the effect of timing of percutaneous coronary intervention (PCI) in acute coronary syndromes (ACS) without persistent ST-segment elevation on the need for repeat revascularization, and we related this effect to other events. BACKGROUND: Percutaneous coronary intervention is widely used to treat ACS without persistent ST-segment elevation. Moreover, restenosis and subsequent revascularization after PCI are more frequent in ACS than in stable angina. The optimal timing of PCI in ACS without persistent ST-segment elevation is unknown. METHODS: In the Platelet glycoprotein IIB/IIIA in Unstable angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) database, patients were stratified by the time of PCI. In the PURSUIT trial, 9,461 patients received a platelet glycoprotein IIb/IIIa inhibitor, eptifibatide or placebo for 72 h. The investigators decided on other treatments. RESULTS: A total of 2,430 patients underwent PCI within 30 days. Repeat revascularization (during 165 days) was notably higher for PCI within 24 h of enrollment (n = 620 [19%]) than for PCI at 24 to 72 h (n = 624 [16.7%]), 3 to 7 days (n = 614 [13.2%]), or 8 to 30 days (n = 561 [7.7%]; p < 0.001), regardless of eptifibatide use. This gradual reduction in the revascularization rate for later PCI was also observed after multivariate analysis correcting for baseline characteristics and with time as a continuous variable. CONCLUSIONS: Percutaneous coronary intervention within 24 is associated with improved outcome (other analysis) but more repeat revascularization. Prospective analyses are needed to test the hypothesis that rapid PCI in ACS with a platelet glycoprotein IIb/IIIa receptor antagonist reduces myocardial infarction (and possibly death) and is therefore most suited for patients at highest risk of infarction, despite a higher need for repeat revascularization.

Aged↗
PubMed2002

Assessment of viable tissue in Q-wave regions by metabolic imaging using single-photon emission computed tomography in ischemic cardiomyopathy.

Chronic electrocardiographic Q waves are often believed to reflect irreversibly scarred, transmurally infarcted myocardium. The aim of this study was to evaluate whether residual viable tissue persists in dysfunctional myocardial regions related to chronic Q waves on the surface electrocardiogram. A total of 148 patients with healed myocardial infarction and impaired left ventricular (LV) function with heart failure symptoms underwent electrocardiography and metabolic imaging using technetium (Tc-99m) tetrofosmin/F18-fluorodeoxyglucose (FDG) single-photon emission computed tomography (SPECT). The left ventricle was divided into 4 major regions to compare myocardial viability in regions with and without chronic Q waves on surface electrocardiography. According to FDG SPECT metabolic imaging, residual viable tissue persisted in a high proportion (61%) of dysfunctional myocardial regions with chronic Q waves. Regions with chronic Q waves were more often dysfunctional than regions without Q waves. Moreover, dysfunctional regions with chronic Q waves were less frequently viable compared with dysfunctional regions without Q waves on the electrocardiogram. This study demonstrates that chronic Q waves on electrocardiography do not necessarily imply irreversibly scarred myocardium. Residual viable tissue persists in a high proportion of dysfunctional ventricular regions according to FDG SPECT metabolic imaging.

Aged↗
PubMed2002

Coronary hemodynamics of stent implantation after suboptimal and optimal balloon angioplasty.

OBJECTIVES: This study was performed to evaluate hemodynamic alterations of stent implantation after Doppler flow-guided balloon angioplasty (BA). BACKGROUND: There is controversy regarding the effect of stent implantation on coronary hemodynamics after suboptimal and optimal BA. METHODS: A total of 523 of 620 patients underwent Doppler-guided BA in the setting of a multicenter study and were analyzed before and after additional stent implantation. Balloon angioplasty was considered optimal when the diameter stenosis (DS) was < or = 35% and coronary flow reserve (CFR) was >2.5 and suboptimal if these two criteria were not met. Coronary flow reserve was also measured in an angiographically normal artery to determine relative CFR. Patients were followed for 12 months to document major adverse cardiac events (MACE). RESULTS: The main difference between patients with suboptimal BA (n = 195 [51%]) and optimal BA (n = 184 [49%]) was a more pronounced increase in baseline blood flow velocity (15 +/- 8 to 22 +/- 11 vs. 14 +/- 8 to 16 +/- 10 cm/s, p < 0.01). Coronary flow reserve improved after stent implantation in both patient groups, owing to a reduction in residual lumen obstruction, as determined by angiographic (%DS) and Doppler flow criteria (hyperemic blood flow velocity, relative CFR), and was associated with a decrease in MACE (16% vs. 7% in optimal BA group, p = 0.08; and 27% vs. 11% in suboptimal BA group, p = 0.007). CONCLUSIONS: Stent implantation enhances CFR after suboptimal and optimal Doppler-guided BA, owing to a reduction in residual lumen obstruction-determined by angiographical and Doppler flow criteria-as the underlying mechanism for an improved clinical outcome.

Aged↗
PubMed2002

Accuracy of PET in predicting functional recovery after revascularisation in patients with chronic ischaemic dysfunction: head-to-head comparison between blood flow, glucose utilisation and water-perfusable tissue fraction.

Accurate prediction of improvement in left ventricular ejection fraction (LVEF) after revascularisation is critical in the therapeutic decision-making process in patients with chronic ischaemic dysfunction. Positron emission tomography (PET) allows non-invasive evaluation of myocardial blood flow (MBF), metabolic rate of glucose (MRG, absolute and relative) and the water-perfusable tissue fraction (PTF). Each of these indices has been proposed for the prediction of functional recovery. Their relative merits, however, are unknown, because a direct head-to-head comparison of their predictive accuracy in the same patients has not been performed. In this study, MBF, MRG (absolute and relative) and PTF were evaluated in 34 patients with severe ischaemic LV dysfunction (LVEF 32%+/-9%). MBF and PTF were determined by oxygen-15 labelled water PET, and MRG (absolute and relative) was determined by fluorine-18 fluorodeoxyglucose (FDG) PET during hyperinsulinaemic euglycaemic clamp. LVEF was measured by radionuclide ventriculography before and 4-6 months after surgery. Sensitivities of MBF, PTF, absolute MRG and relative MRG in predicting improvement in LVEF were 80%, 80%, 90% and 100%, respectively. Their specificities were 54%, 67%, 71% and 71%, respectively. The lowest specificity was obtained for MBF, an intermediate specificity was obtained for PTF and the highest specificities were obtained with FDG PET using absolute and relative MRG. It is concluded that metabolic imaging is superior to perfusion-based indexes for assessment of the potential for functional recovery after revascularisation.

Adult↗
PubMed2002

Feasibility, safety and image quality of cardiac FDG studies during hyperinsulinaemic-euglycaemic clamping.

Fluorine-18 fluorodeoxyglucose (FDG) imaging for the assessment of myocardial viability has become an integral part of the diagnostic and prognostic work-up of patients with ischaemic cardiomyopathy. To ensure good image quality, in particular in patients with diabetes mellitus, hyperinsulinaemic-euglycaemic clamping has been proposed. In this study we evaluated the safety and the image quality of cardiac FDG imaging during clamping in a large group of patients, including a subgroup with diabetes mellitus. The incidence of viability (on both a segment and a patient basis) was also determined for patients with and without diabetes mellitus. The safety and image quality of cardiac FDG studies during clamping were evaluated in 131 patients, including 19 with diabetes mellitus. Image quality was assessed visually and quantitatively using heart-to-lung (H/L), heart-to-liver (H/Li) and myocardium-to-background (M/B) ratios. Blood samples were drawn at baseline and at the time of FDG injection to determine levels of glucose, free fatty acids and insulin. The metabolic circumstances were optimal for FDG imaging: high insulin levels, low free fatty acid levels and glucose levels in the normal range (levels of substrates were comparable between patients with and patients without diabetes mellitus). No serious side-effects occurred in any patient. Image quality (assessed visually) was good in all patients. The quantitative parameters of image quality (H/L, H/Li and M/B) were comparable between patients with and patients without diabetes mellitus. The incidence of viability was high: 38% of patients without and 58% of patients with diabetes mellitus had substantial viability despite contractile dysfunction. It is concluded that cardiac FDG imaging during clamping is safe and provides excellent image quality, including in patients with diabetes mellitus. The incidence of viability is high, in particular in patients with diabetes mellitus.

Aged↗
PubMed2002

Minor myocardial damage and prognosis: are spontaneous and percutaneous coronary intervention-related events different?

BACKGROUND: The relevance of the adverse prognostic implications of CK-MB elevation after percutaneous coronary intervention (PCI) remains controversial. Therefore, we compared the relationship between the level of postprocedural CK-MB elevation and 6-month mortality in patients undergoing PCI with the relationship between the level of spontaneous, non-PCI-related CK-MB elevation and 6-month mortality in patients with acute coronary syndromes (ACS) treated medically. METHODS AND RESULTS: In the PURSUIT trial, 5583 of 9461 patients who presented with a non-ST-elevation ACS did not undergo PCI or CABG and had at least 1 CK-MB sample collected during index-hospitalization. There was a gradual increase in 6-month mortality with higher CK-MB levels: 4.1%, 8.6%, 9.0%, 14.3%, 15.5% for CK-MB ratios 0 to 1, >1 to 3, >3 to 5, >5 to 10, and >10 times the upper limit of normal. A combined analysis in 8838 patients undergoing PCI in 5 large, clinical trials revealed a proportional relationship between postprocedural CK-MB levels (</= 48 hours after PCI) and 6-month mortality. In patients with CK-MB ratios 0 to 1, >1 to 3, >3 to 5, >5 to 10, and >10, the risk of death was 1.3%, 2.0%, 2.3%, 4.3%, and 7.4%, respectively. The absolute mortality rates were lower after procedure-related infarcts compared with spontaneous infarcts. Yet, the relative increase in 6-month mortality with each increase in peak CK-MB level was similar for PCI-related myocardial necrosis and spontaneous myocardial necrosis, as all tests for heterogeneity of the odds ratios were nonsignificant. CONCLUSIONS: The present analysis indicates that the adverse prognostic implications of periprocedural myocardial necrosis should be considered similar to the adverse consequences of spontaneous myocardial necrosis.

Angioplasty, Balloon, Coronary↗
PubMed2002

Platelet glycoprotein IIb/IIIa inhibitors in acute coronary syndromes: a meta-analysis of all major randomised clinical trials.

BACKGROUND: Platelet glycoprotein IIb/IIIa inhibitors have been shown to reduce cardiac complications in patients undergoing percutaneous coronary intervention. The clinical efficacy of these drugs in acute coronary syndromes, however, is still unclear. We did a meta-analysis of all large randomised trials designed to study the clinical efficacy and safety of glycoprotein IIb/IIIa inhibitors in patients with acute coronary syndromes who were not routinely scheduled to undergo early coronary revascularisation. METHODS: Inclusion criteria were: randomisation of patients with acute coronary syndromes but without persistent ST elevation; comparison of a glycoprotein IIb/IIIa inhibitor with placebo or control therapy; non-recommendation of early coronary revascularisation during study-drug infusion; and enrollment of at least 1000 patients. Data on individual patients were obtained from all participants in these trials. FINDINGS: Six trials, enrolling 31402 patients, fulfilled the inclusion criteria. 30 days after randomisation, 3530 (11.2%) patients died or developed a myocardial infarction. At 30 days, a 9% reduction in the odds of death or myocardial infarction was seen with glycoprotein IIb/IIIa inhibitors compared with placebo or control (10.8% [1980/18297] vs 11.8% [1550/13105] events; odds ratio 0.91 [95% CI 0.84-0.98]; p=0.015). The relative treatment benefit was similar in subgroups of patients according to important clinical baseline characteristics; hence, the absolute treatment benefit was largest in high-risk patients. An unexpected and significant interaction was seen between sex and allocated treatment, with a treatment benefit in men (0.81 [0.75-0.89] but not in women (1.15 [1.01-1.30]). However, once patients were stratified according to troponin concentration, there was no evidence of a sex difference in treatment response, and a risk reduction was seen in men and women with raised troponin concentrations. Major bleeding complications were increased by glycoprotein IIb/IIIa inhibitors (2.4% [445/18297] vs 1.4% [180/13105]; p<0.0001), but intracranial bleeding was not (16 [0.09%] vs 8 [0.06%]; p=0.40). INTERPRETATION: Glycoprotein IIb/IIIa inhibitors reduce the occurrence of death or myocardial infarction in patients with acute coronary syndromes not routinely scheduled for early revascularisation. The event reduction is greatest in patients at high risk of thrombotic complications. Treatment with a glycoprotein IIb/IIIa inhibitor might therefore be considered especially in such patients early after admission, and continued until a decision about early coronary revascularisation has been made.

Aged↗
PubMed2002

A new intracoronary measurement catheter, MetriCath, compared to intravascular ultrasound and quantitative coronary angiography in a stented porcine coronary model.

The purpose of this study was to compare measurements by MetriCath to intravascular ultrasound (IVUS) and quantitative coronary angiography (QCA). The MetriCath system consists of a low-pressure (200 mm Hg) balloon catheter connected to a pressure transducer and infusion pump linked to a computer that records pressure-volume curves. Cross-sectional area of blood vessels is obtained directly from the unrestrained and in-stent pressure-volume measurements. We compared stent cross-sectional area measurements by MetriCath, IVUS, and QCA in a porcine stented coronary artery model. Comparison of area measurements in 14 stents showed no significant differences between the three methods (P = 0.66). On average, values differed 0.37 +/- 0.60 mm(2) between MetriCath and QCA, 0.13 +/- 0.55 mm(2) between MetriCath and IVUS, and 0.22 +/- 0.80 mm(2) between IVUS and QCA. This corresponds to 6.2% +/- 10%, 3.0% +/- 9.0%, and 3.1% +/- 12.9% relative difference from the average of two corresponding measurements. Linear regression analysis showed excellent correlation between measurements (r = 0.99 for all comparisons). The differences in in-stent area measurements between MetriCath and both QCA and IVUS were small. Considering the ease and rapidity of obtaining MetriCath results, this technique may form an alternative to the others in evaluating stent expansion. Based on these findings, clinical evaluation seems warranted.

Animals↗
PubMed2002

Contribution of nursing to risk factor management as perceived by patients with established coronary heart disease.

BACKGROUND: Guidelines stress the importance of risk factor management in patients with coronary heart disease (CHD). AIMS: To evaluate whether guidelines on patient education in risk factor management are followed in clinical practice and to assess the contribution of nursing to risk factor management as perceived by patients with established CHD. METHODS: Within three Dutch hospitals consecutive patients were identified after a first coronary-artery bypass graft, a first percutaneous transluminal coronary angioplasty or hospital admission for acute myocardial infarction or ischaemia (n=357). Data were collected through patient interviews at least 6 months after hospital admission. RESULTS: Among smokers, overweight patients, patients with hypertension, high cholesterol, and sedentary lifestyle, respectively 75, 36, 67, 61 and 49% reported that information on presence or management of these risk factors was provided. The proportion of patients informed by nurses ranged from 14% (lowering cholesterol) to 23% (increasing physical activity), while 55% (lowering cholesterol) to 71% (stop smoking) were informed by physicians. CONCLUSION: Many patients with established CHD and cardiovascular risk factors do not remember ever having received information about management of their risk factors. Clearly, there is a substantial potential to improve professionals' compliance to guidelines on risk factor management, including those on patient education. The perceived contribution of nurses to risk factor management is small compared to that of physicians and other caregivers. If risk factor management is felt to be a main responsibility of nurses, current nursing activities in this area should be reconsidered within an improved organisational structure.

Coronary Disease↗
PubMed2002

Assessment of residual myocardial viability in regions with chronic electrocardiographic Q-wave infarction.

BACKGROUND: Q waves on the electrocardiogram are often considered to be reflective of irreversibly scarred myocardium due to antecedent transmural myocardial infarction. However, there are some indications that residual viable tissue may be present in Q-wave-infarcted regions. It is clinically relevant to know how many Q-wave regions contain viable tissue because these patients may benefit from revascularization in terms of improvement of function and long-term survival. METHODS: Patients (n = 150) with chronic electrocardiographic Q-wave infarction, heart failure symptoms, and chronic coronary artery disease underwent dobutamine-atropine stress echocardiography to assess myocardial viability. Residual viability in regions with Q-wave infarction was considered present when the end-diastolic wall thickness (EDWT) was >6 mm and the response during dobutamine infusion indicated viable tissue. RESULTS: Baseline echocardiography revealed 517 dysfunctional myocardial regions; 202 of the dysfunctional regions were related to Q waves on the electrocardiogram and the other 315 dysfunctional regions were not. EDWT was < or =6 mm in 13 regions with a Q wave on the electrocardiogram, with only 1 region exhibiting viable tissue during dobutamine stress echocardiography. EDWT was >6 mm in 189 regions with a Q wave, with 118 (62%) having viable tissue on dobutamine stress echocardiography. In 6 dysfunctional regions without a Q wave, EDWT was < or =6 mm, with all being nonviable on dobutamine stress echocardiography; of the 309 regions without a Q wave and EDWT >6 mm, 204 (66%) exhibited viability on dobutamine stress echocardiography. CONCLUSIONS: Fifty-eight percent of dysfunctional regions related to chronic Q waves were viable according to the combined information of EDWT and dobutamine stress echocardiography. EDWT </=6 mm virtually excludes viability; regions with EDWT >6 mm need additional testing to detect or exclude viability.

Cardiac Output, Low↗