Fractional flow reserve and instantaneous wave free ratio in 2015.

In the recent years it has become apparent that angiography-based assessment of coronary artery stenosis suffers from considerable inaccuracy and pitfalls. Besides interobserver variability in assessing stenosis severity, the correlation between angiographic severity and ischemia is suboptimal. Percutaneous coronary intervention (PCI) guided by the physiologic lesion assessment employing fractional flow reserve (FFR) is rendered superior to angiographic lesion assessment and proven to improve cardiovascular outcomes and reduce cost. In this manuscript we discuss the accepted and emerging clinical indications for FFR use. The correlation between FFR and symptoms, stress imaging and intravascular ultrasound are reviewed along with the inherent limitations and pitfalls of these diagnostic technologies. The data regarding the correlation between Instantaneous (vasodilator free) wave-free ratio (iFR) and conventional FFR is summarized.

Advanced therapeutic options in pulmonary hypertension: who, what and when?

Pulmonary hypertension (PH) is the common hemodynamic consequence of various pathophysiologic mechanisms. Since the publication of the most current American and European guidelines (2009) new agents were introduced into the clinical arena while data regarding former drugs has been substantiated. The therapeutic endeavor of evaluating new therapies for PH targets patients based on their PH type and symptom severity with the hope to demonstrate hemodynamic and functional benefits along with reduction in morbidity and mortality. Although patients' outcomes (predominantly among type I and IV) have improved, the hemodynamic and symptomatic benefit is modest and not uniform. The purpose of this review is to objectively assess the benefits of the currently available dedicated agents. It is our hope that with early detection and careful individual titration of new combination therapy in expert hands, we will better serve a larger proportion of our PH patients.

Saving the patient with post-ACS cardiogenic shock.

The adoption of early revascularization as the preferred strategy in all ST-elevation myocardial infarctions (STEMI) and high risk acute coronary syndromes (ACS) without ST elevation resulted in a considerable reduction in the incidence of post-ACS cardiogenic shock (CS) however the incidence of CS on hospital arrival has not changed. In-hospital and 30 day mortality from CS remains excessively high in facilities with coronary revascularization capabilities. Trials investigating the incremental value of either intra-aortic counter-pulsation (IACP) or advanced MCS did not demonstrate a meaningful mortality reduction. Mortality remains 45-60% and depends on clinical characteristics of the patient, timely and successful revascularization and advanced MCS in suitable candidates. Most CS survivors demonstrate satisfactory functional capacity and quality of life. The authors propose the "Guthrie classification" for post-ACS CS. This classification promotes better characterization of CS patients enrolled in clinical trials and registries. It also allows the clinician to better define the goals and benefits of therapy for the CS subjects. The precise pathophysiology of post-ACS CS remains poorly understood at the biochemical and cellular level. Uncovering and modifying these processes remains key to any fundamental change in post-ACS CS outcomes.

Fractional flow reserve at 2013: an update.

Fractional flow reserve (FFR) has become an extremely valuable tool for assessing the hemodynamic significance of intermediate coronary lesions in patients with stable coronary syndromes. This manuscript delineates the current data supporting FFR use to guide cardiovascular interventions in comparison to other invasive and non-invasive modalities. The correlation between FFR, symptom severity and likelihood of future major cardiovascular events are critically examined in view of the FAME-2 study results. The authors delineate the scientific gaps, potential pitfalls and misconceptions related to FFR with regards to current and emerging indications. Described are the most important developments related to FFR in 2012: instantaneous wave free ratio and non-invasive CT angiography based FFR. The manuscript proposes areas of future research to enhance the scientific data supporting current FFR clinical algorithms and strategies.

Dual antiplatelet therapy for primary and secondary prevention.

The concomitant use of aspirin and an ADP receptor (P2Y12) blocker, also known as dual antiplatelet therapy (DAPT), has been extensively investigated as a primary and secondary prevention strategy in an effort to reduce the risk of cardiovascular events. In this manuscript the authors review the current guideline recommendations for DAPT and discuss the scientific data that supports these recommendations. Reported are also the scientific knowledge gaps and how future studies are likely to delineate these issues. Incremental knowledge is not likely to be an alternative to individualized care provided by the astute clinician to his patient. In consideration for prescribing DAPT (drug, dosage and duration) the clinician will have to weigh the potential benefits (reduction in death from cardiovascular causes, nonfatal myocardial infarction, and nonfatal stroke) and risks (severe or life-threatening bleeding) for each and every patient.

Fractional flow reserve (FFR): changing the practice of interventional cardiology.

Fractional flow reserve (FFR) has become an extremely valuable tool for assessing the hemodynamic significance of intermediate coronary lesions. This manuscript delineates the current guidelines regarding the use of FFR and discusses emerging indications for the use of this diagnostic tool and how they compare with and complement non-invasive or other invasive diagnostic modalities. The manuscript addresses some of the key unanswered questions related to FFR, the potential pitfalls of this tool and discusses future directions of use and research.

Emerging oral anticoagulants for stroke prevention in patients with non-valvular atrial fibrillation.

In patients with atrial fibrillation (AF) warfarin has been the mainstay therapy for stroke prevention. In recent randomized clinical trials (RCTs) oral direct thrombin inhibitor (Dabigatran) and factor Xa inhibitors (Rivaroxaban and Apixaban) challenged the efficacy and safety benchmarks set by warfarin. These drugs boast a rapid onset of action, shorter half-life and fewer drug and dietary interactions. Moreover, these new anticoagulants do not require monitoring, titration or dose adjustments. These agents have already been approved for prevention of stroke or systemic embolism in patients with AF. Uncertainty regarding suitability, efficacy and safety in certain patient subsets and issues related to the ability effectively monitor the pharmacodynamic effects and reverse the therapeutic effects of these drugs should be addressed as we engage in a widespread use of these agents in various patient subsets.

Routine stress testing after percutaneous coronary interventions.

Percutaneous coronary intervention (PCI) is the most frequently performed cardiovascular procedure. Many physicians caring for post-PCI patients have routinely subjected patients to periodic stress testing. In the recent years, due to widespread use of drug eluting stents the combined rates of major adverse cardiac events (MACE) and in-stent restenosis (ISR) dropped <10% in the initial 12 months post-PCI, with only half of these patients bearing symptoms. This has translated into reduced pre-test probability of post-PCI ischemia. Consequently, the beneficial effect of this practice came into question. Moreover, in addition to its financial implications, routine post-PCI stress testing may carry potential harm: medication or exercise induced arrhythmia, infarction and/or death, patient irradiation exposure, false-positive tests resulting in excessive invasive testing or interventions, and the illusion of "wellness" in the face of a somewhat unpredictable disease. This review addresses the role stress testing post-PCI: it is concluded that routine stress testing in clinically stable asymptomatic post-PCI patients should be discouraged. Selective utilization of stress testing in patients with exceptionally high risk of ISR or MACE can be utilized to answer important clinical questions or guide and refine clinical care.

Clinical applicability of coronary atherosclerotic lesion characterization.

Native coronary atherosclerosis (CAS) is a diffuse and progressive disease process that is occasionally associated with either clinical atherothrombosis and/or major adverse cardiac events (MACE) including: ST elevation myocardial infarction (STEMI), acute coronary syndromes without ST elevation (ACSWSTE), heart failure, cardiac arrest and sudden cardiac death. Both, the timing and coronary site responsible for the MACE are currently unpredictable. Cardiovascular investigators have engaged in the task of characterizing CAS lesions in order to enhance our knowledge of CAS pathophysiology. It was expected that the knowledge acquired will allow scientists and clinicians to develop effective strategies to detect and treat "vulnerable plaque" (VP) prior to the evolution of MACE. This review discusses the emerging data regarding the pathology and natural history of the VP and vulnerable patient and the progress made in characterizing atherosclerotic plaque instability and vulnerability. Future directions in the field of plaque characterization and their potential clinical and research applications are discussed.

Aspirin for the prevention of cardiovascular morbidity.

Aspirin (ASA) use for secondary prevention in patients with cardiovascular (CV) disease is well established through its beneficial effects on the reduction of myocardial infarction, ischemic stroke and CV mortality. This beneficial effect of ASA seems to consistently outweigh the risk in most patient subsets. Current guidelines endorse ASA for primary prevention of CV events in adults who are at moderate-high risk of CV morbidity. Recent emerging data on the efficacy and safety of ASA conflicts with former randomized clinical trials and raises concerns regarding the validity of these recommendations. The following manuscript describes the data emerging from contemporary trials regarding the efficacy and safety of ASA in various patient subsets. The authors propose certain strategies to enhance safety and efficacy in order to augment the beneficial effects of ASA along with other modalities of primary prevention for suitable candidates. When contemplating ASA prescription for primary prevention of CV events, physicians should carefully weigh the potential benefits of risk reduction versus likelihood of harm, mostly related to bleeding complications.

The management of acute heart failure.

Hospitalization for acute heart failure (AHF) is one of the burdensome aspects of 21st century medicine, leading to significant debilitating symptoms, high morbidity and mortality and consuming significant portion of the health care budget. Management of AHF is thought-provoking given the heterogeneity of the patient population, absence of a universally accepted definition, incomplete understanding of the pathophysiology and the beneficial and adverse effects of currently used therapies and lack of robust evidence-based guidelines. The article will discuss the clinical approach to the patients admitted with AHF, reviewing types of intervention (both approved and investigational) and will delineate their role and timing in specific AHF presentations. One of the challenges of AHF management is to effectively treat the subsets of patients with slow improvement or those with refractory AHF or early recurrence (worsening HF) during their initial admission. Unfortunately, the majority of these patients are at increased risk for subsequent complications and adverse outcomes. Therefore, considerable efforts in AHF management should be directed towards this population. Regretfully, to date no specific targeted therapy was proven beneficial for these patients, being one of the leading reasons for the lack of improvement in AHF outcomes over the last 30 years.

A prospective study of posttraumatic stress symptoms and nonadherence in survivors of a myocardial infarction (MI).

We examined a novel hypothesis that links symptoms of MI-related posttraumatic stress disorder (PTSD) to nonadherence. According to this hypothesis, patients who are traumatized by their medical illness do not take their medications as prescribed. As a part of the avoidance dimension of PTSD, patients who are traumatized may avoid being reminded of the MI by not taking the medication. MI survivors were prospectively followed for 6 months to 1 year. Adherence was assessed by pill count of Captopril. Demographic variables, medical risk factors, PTSD, and other psychiatric symptom dimensions were evaluated during follow-up. One hundred two of 140 recruited patients completed follow-up. Nonadherence to Captopril was associated with poor medical outcome (r=.93, P=.006). Above-Threshold PTSD symptoms were associated with nonadherence to medications (P=.05). No other psychiatric symptom dimensions were independently associated with nonadherence. Nonadherence to medications predicts adverse outcome during the first year after an acute MI. Nonadherence is associated with PTSD symptoms, which may either be a marker for or a cause of nonadherence. Treatment of PTSD may prove to be a useful approach for improving adherence.

Tezosentan (an intravenous endothelin receptor A/B antagonist) reduces peripheral resistance and increases cardiac power therefore preventing a steep decrease in blood pressure in patients with congestive heart failure.

OBJECTIVE: This study investigated the effect of tezosentan (an intravenous endothelin-1 receptor antagonist) on vascular resistance and cardiac function and determined the dose response in patients with stable congestive heart failure (CHF) due to left ventricular systolic dysfunction. METHODS: In a double-blind fashion, tezosentan or placebo were administered in ascending doses (5, 20, 50, 100 mg h(-1)) to 38 CHF (NYHA class III) patients with ejection fraction or=15 mmHg. Systemic vascular resistance index (SVRi) was estimated as mean arterial blood pressure [(MAP-right atrial pressure)/cardiac index (CI)]. Cardiac function was assessed as cardiac power index (Cpi), calculated as pressure x flow (MAP x CI), where MAP represents pressure and CI represents cardiovascular flow. RESULTS AND DISCUSSION: Compared to the placebo, tezosentan induced a dose-dependent decrease in SVRi (-32%), an increase in Cpi (+20%) and a small decrease in MAP (-9%). By contrast, patients treated with nitrate vasodilators or nesiritide (a natriuretic peptide) showed a decrease in SVRi not accompanied by a significant increase in Cpi leading to a steep decrease in MAP. CONCLUSIONS: The use of Cpi in the assessment of the hemodynamic effects of tezosentan, provides a useful alternative characterization of the complex influences of vasodilators on cardiac function in patients with CHF.

Pulmonary edema: new insight on pathogenesis and treatment.

Pulmonary edema is one of the most serious and life-threatening situations in emergency medicine. Lately it has become apparent that in most cases pulmonary edema is not caused by fluid accumulation but rather fluid redistribution that is directed into the lungs because of heart failure. Based on a series of recently published studies, we propose that often the pathogenesis of pulmonary edema is related to a combination of marked increase in systemic vascular resistance superimposed on insufficient systolic and diastolic myocardial functional reserve. This resistance results in increased left ventricular diastolic pressure causing increased pulmonary venous pressure, which yields a fluid shift from the intravascular compartment into the pulmonary interstitium and alveoli, inducing the syndrome of pulmonary edema. Therefore, the emphasis in treating pulmonary edema has shifted from diuretics (ie, furosemide) to vasodilators (ie, high-dose nitrates) combined with noninvasive positive airway pressure ventilation and rarely inotropes. New classes of drugs that are currently being investigated for treating decompensated heart failure such as natriuretic peptides, calcium promoters, and endothelin antagonist are also being assessed for treating pulmonary edema. This review will explore this new hypothesis put forward to explain the pathogenesis of pulmonary edema and the evolving management strategies.

High-dose intravenous isosorbide-dinitrate is safer and better than Bi-PAP ventilation combined with conventional treatment for severe pulmonary edema.

OBJECTIVE: To determine the feasibility, safety and efficacy of bilevel positive airway ventilation (BiPAP) in the treatment of severe pulmonary edema compared to high dose nitrate therapy. BACKGROUND: Although noninvasive ventilation is increasingly used in the treatment of pulmonary edema, its efficacy has not been compared prospectively with newer treatment modalities. METHODS: We enrolled 40 consecutive patients with severe pulmonary edema (oxygen saturation <90% on room air prior to treatment). All patients received oxygen at a rate of 10 liter/min, intravenous (IV) furosemide 80 mg and IV morphine 3 mg. Thereafter patients were randomly allocated to receive 1) repeated boluses of IV isosorbide-dinitrate (ISDN) 4 mg every 4 min (n = 20), and 2) BiPAP ventilation and standard dose nitrate therapy (n = 20). Treatment was administered until oxygen saturation increased above 96% or systolic blood pressure decreased to below 110 mm Hg or by more than 30%. Patients whose conditions deteriorated despite therapy were intubated and mechanically ventilated. All treatment was delivered by mobile intensive care units prior to hospital arrival. RESULTS: Patients treated by BiPAP had significantly more adverse events. Two BiPAP treated patients died versus zero in the high dose ISDN group. Sixteen BiPAP treated patients (80%) required intubation and mechanical ventilation compared to four (20%) in the high dose ISDN group (p = 0.0004). Myocardial infarction (MI) occurred in 11 (55%) and 2 (10%) patients, respectively (p = 0.006). The combined primary end point (death, mechanical ventilation or MI) was observed in 17 (85%) versus 5 (25%) patients, respectively (p = 0.0003). After 1 h of treatment, oxygen saturation increased to 96 +/- 4% in the high dose ISDN group as compared to 89 +/- 7% in the BiPAP group (p = 0.017). Due to the significant deterioration observed in patients enrolled in the BiPAP arm, the study was prematurely terminated by the safety committee. CONCLUSIONS: High dose ISDN is safer and better than BiPAP ventilation combined with conventional therapy in patients with severe pulmonary edema.

Minimal heparinization in coronary angioplasty--how much heparin is really warranted?

The purpose of the study was to assess the results of percutaneous transluminal coronary angioplasty (PTCA), performed with a single intravenous bolus of 2,500 U of heparin, in a nonemergency PTCA cohort. Three hundred of 341 consecutive patients (87.9%) undergoing PTCA were prospectively enrolled in the study. They received heparin, 2,500-U intravenous bolus, before PTCA, with intention of no additional heparin administration. Patient and lesion characteristics as well as PTCA results were evaluated independently by 2 physicians. Patients were followed up by structured telephone questionnaires at 1 and 6 months after PTCA. Mean activated clotting time obtained 5 minutes after heparin administration was 185+/-19 seconds (range 157 to 238). There were 3 (1%) in-hospital major adverse cardiovascular events: 2 deaths (0.66%), 1 (0.33%) Q-wave myocardial infarction. Emergency coronary surgery and stroke were not reported. Six patients (2%) experienced abrupt coronary occlusion within 14 days after PTCA, warranting repeat target vessel revascularization. Angiographic and clinical success were achieved in 96% and 93.3%, respectively. No bleeding or vascular complications were recorded. Six-month follow-up (184 patients) revealed 3 cardiac deaths (1 arrhythmic, 2 after cardiac surgery), 1 Q-wave myocardial infarction, and 9.7% repeat target vessel revascularization. This study suggests that very low doses of heparin and reduced activated clotting time target values are safe in non-emergency PTCA, and can reduce bleeding complications, hospital stay, and costs. Larger, randomized, double-blind heparin dose optimization studies need to confirm this notion.

L-NMMA (a nitric oxide synthase inhibitor) is effective in the treatment of cardiogenic shock.

BACKGROUND: The objective was to assess the safety and efficacy of L-NMMA in the treatment of cardiogenic shock. METHODS: We enrolled 11 consecutive patients with cardiogenic shock that persisted after >24 hours from admission, despite coronary catheterization and primary percutaneous transluminal coronary revascularization, when feasible, and treatment with mechanical ventilation, intraaortic balloon pump (IABP), and high doses of catecholamines. L-NMMA was administered as an IV bolus of 1 mg/kg and continuous drip of 1 mg. kg(-1). h(-1) for 5 hours. Treatment with catecholamines, mechanical ventilation, and IABP was kept constant throughout the study. RESULTS: Within 10 minutes of L-NMMA administration, mean arterial blood pressure (MAP) increased from 76+/-9 to 109+/-22 mm Hg (+43%). Urine output increased within 5 hours from 63+/-25 to 156+/-63 cc/h (+148%). Cardiac index decreased during the steep increase in MAP from 2. 0+/-0.5 to 1.7+/-0.4 L/(min. m(2)) (-15%); however, it gradually increased to 1.85+/-0.4 L/(min. m(2)) after 5 hours. The heart rate and the wedge pressure remained stable. Twenty-four hours after L-NMMA discontinuation, MAP (+36%) and urine output (+189%) remained increased; however, cardiac index returned to pretreatment level. No adverse events were detected. Ten out of eleven patients could be weaned off mechanical ventilation and IABP. Eight patients were discharged from the coronary intensive care unit, and seven (64%) were alive at 1-month follow-up. CONCLUSIONS: L-NMMA administration in patients with cardiogenic shock is safe and has favorable clinical and hemodynamic effects.

Conversion of recent onset paroxysmal atrial fibrillation to normal sinus rhythm: the effect of no treatment and high-dose amiodarone. A randomized, placebo-controlled study.

BACKGROUND: Spontaneous conversion of recent onset paroxysmal atrial fibrillation to normal sinus rhythm occurs commonly and is not affected by low-dose amiodarone treatment. METHODS: In a randomized, placebo-controlled trial of 100 patients with paroxysmal atrial fibrillation of recent onset (<48 h) we compared the effects of treatment with continuous intravenous amiodarone 125 mg per hour (total 3 g) and intravenous placebo. Patients in the placebo group who did not convert to normal sinus rhythm within 24 h were started on amiodarone therapy. RESULTS: Conversion to normal sinus rhythm occurred within 24 h in 32 of 50 patients (64%) in the placebo group, most of whom converted within 8 h. Lower conversion rates were observed in patients with hypertension, ischaemic heart disease or congestive heart failure and in patients with echocardiographic findings of left atrial diameter above 45 mm, ejection fraction below 45% or significant mitral regurgitation. However, in most patients these clinical or echocardiographic risk factors of decreases in conversion rate were not present. In such patients the spontaneous conversion rate was approximately 90%. The conversion rate during 24 h of treatment in the amiodarone group was 92% (P=0.0017, compared to the placebo group). In this group, the conversion rate was largely unaffected by baseline characteristics. Of the 18 patients who did not convert with placebo, 15 (85%) converted after being crossed over to amiodarone. All patients not responding to high-dose amiodarone were in chronic atrial fibrillation within 1 month. In patients still in atrial fibrillation after 8 h of treatment, the pulse rate decreased significantly more in the amiodarone as compared to the placebo group (83+/-15 vs 114+/-20 beats. min(-1), P=0.0014). CONCLUSION: The spontaneous conversion of recent onset paroxysmal atrial fibrillation is high and approaches 90% in specific clinical and echocardiographically defined subgroups. Intravenous high-dose amiodarone safely facilitates conversion of paroxysmal atrial fibrillation. However, such treatment should be reserved for patients with unfavourable risk factor profiles, not converting during 8 h of observation or requiring rate control.

Usefulness of losartan, captopril, and furosemide in preventing nitrate tolerance and improving control of unstable angina pectoris.

Sixty consecutive normotensive patients with unstable angina pectoris, who were on continuous intravenous isosorbide dinitrate (ISDN) treatment and had not previously received angiotensin II receptor antagonists, angiotensin-converting enzyme (ACE) inhibitors, or diuretics were randomly assigned to treatment groups receiving intravenous ISDN for 72 hours. No additional treatment was given to group A (n = 15). Captopril, in a test dose of 6.25 mg, and followed by 12.5 mg 3 times daily for 24 hours and 25 mg 3 times daily for the next 24 hours, was given to group B (n = 15). The same dose of captopril plus 40 mg of furosemide in the morning were given to group C (n = 15). Losartan, in a single dose of 25 mg/day and increased to 50 mg after 24 hours was given to group D (n = 15). Nitrate tolerance was evaluated at 24-hour intervals at trough levels of each of the drugs by administering intravenous ISDN (1 mg bolus dose every 4 minutes) and recording the total ISDN test dose required to decrease the mean arterial blood pressure by > or =10%. Treatment with continuous ISDN only (group A) induced nitrate tolerance. The ISDN (mean +/- SD) test dose was 3.5 +/- 1.8 mg at baseline, increasing to 4.9 +/- 2.4 mg at 24 hours, and 8.0 +/- 3.0 mg at 48 hours. The addition of increasing doses of captopril to the continuous ISDN treatment (group B) completely prevented nitrate tolerance. Losartan, however, did not attenuate nitrate tolerance at 24 hours and attenuated it only partially at 48 hours. The addition of furosemide to captopril had no further effect on nitrate tolerance. Of 15 patients in group A (ISDN only), 4 (27%) experienced recurrent ischemic events requiring urgent coronary catheterization. No such events were recorded in group B (captopril), but did occur in 1 patient in each of group C (captopril plus furosemide) and D (losartan) (p = 0.083). Thus, the addition of captopril to the ISDN treatment regimen prevented tolerance to nitrates and improved angina control with apparent safety. Losartan also decreased nitrate tolerance, although to a lesser extent, and also improved angina control. The addition of furosemide to captopril conferred no further benefit.