When compared to 12-month dualantiplatelet therapy ( DAPT ), 6-month DAPT did not increase cardiac events such as myocardial infarction ( MI ) or stroke in patients who underwent everolimus-eluting stent implantation , according to research published in JACC : Cardiovascular Interventions and presented at EuroPCR in Paris .

Guidelines from the ACC and American Heart Association recommend that DAPT be administered for at least 12 months after drug-eluting stent ( DES ) implantation , while the European Society of Cardiology ’ s guidelines allow 6-month DAPT for new-generation DES-treated patients for stable coronary disease treatment .

Between Oct . 2010 and July 2014 , 1,400 patients were randomly assigned to receive either 6-month or 12-month DAPT . Aspirin and clopidogrel adherence rates at 6 months were 98.9 % and 98.9 %, respectively , for the 6-month DAPT groups ; they were 99.5 % and 99.5 %, respectively , for the 12-month groups . At 12 months , the rates of aspirin and clopidogrel use were 99.2 % and 9.3 %, respectively , in the 6-month group and 98.8 % and 98.2 %, respectively , in the 12-month group . Baseline clinical , angiographic , and procedural characteristics results were well balanced in both groups .

The primary endpoint — a composite of cardiac death , MI , stroke , or thrombolysis in myocardial infarction ( TIMI ) major bleeding — occurred in 2.2 % of patients in the 6-month group and 2.1 % of patients in the 12-month group . There were no significant betweengroup differences in the rate for each clinical event , including cardiac death , myocardial infarction , repeat revascularization of stented lesions , stroke , and TIMI major bleeding . These findings were consistent across subgroups of patients with acute coronary syndrome and diabetes mellitus .

A significant interaction was observed with the use of intravascular ultrasound and the duration of DAPT , which , according to the authors , suggests that prolonged DAPT tended to have better clinical outcomes not in

patients with intravascular ultrasound guidance but in those with angiographic guidance . This also suggests that intravascular ultrasound guidance with stent optimization might have more favorable outcomes in patients with shorter duration of DAPT , possibly through fewer bleeding episodes and similar ischemic events .

The authors , led by Sung-Jin Hong , MD , write that “ optimal DAPT strategies after new-generation DES implantation remain to be determined . Optimal DAPT strategies after everolimus-eluting stent implantation are also not clearly established , even though this stent the most extensively evaluated and widely used new-generation DES in daily clinical practice .”

Hong S , Shin D , Kim J , et al . JACC Cardiovasc Interv . 2016 ; doi : 10.1016 / j . jcin . 2016.04.036

High mechanical index ( HMI ) impulses from a diagnostic ultrasound ( DUS ) transducer , combined with microbubble infusion , may prevent microvascular obstruction and improve functional outcome when added to the percutaneous coronary intervention ( PCI ) management of acute ST-segment elevation myocardial infarction ( STEMI ), according to a recent study in JACC .

Prior studies suggest that HMI impulses might enhance myocardial perfusion in patients with STEMI . Researchers randomized patients undergoing primary PCI to HMI before and for 30 minutes after primary PCI ( n = 20 ) versus diagnostic ultrasound only ( n = 10 ) using 5 % Definity contrast . Initial epicardial flow and final microvascular flow were compared between the two groups . Another 70 patients who presented for primary PCI during a time window when ultrasound was not available served as controls .

The average period of DUS therapy time for the HMI + PCI groups prior to PCI was 14 ± 10 min ( range 4 to 44 min ). In patients randomized to ultrasound , the infarct-related vessel was left anterior descending ( LAD )/

— Sung-Jin Hong , MD , et al .

diagonal in 18 cases , right coronary artery in 8 , and left circumflex in 4 . The LAD territory was the infarct vessel in 8 of 10 low mechanical index ( LMI ) + PCI patients and 13 of 20 HMI + PCI patients . Infarct locations in the 70 PCI-only patients were 30 LAD , 26 right coronary artery , and 14 left circumflex territories .

In patients treated with LMI + PCI , ≥ 20 % ST-segment resolution was seen prior to PCI ( after the first ultrasound treatment ) in 10 of 20 ( 50 %) patients , but in only one in 10 patients randomized to LMI + PCI ( p = 0.03 ). Following PCI and at hospital discharge , there were no differences in ST-segment resolution between these groups .

Angiographic recanalization was present in 60 % of the HMI group versus 10 % of the diagnostic scan and 23 % of the control group . HMI was associated with reduced microvascular obstruction and improved left ventricular function at 30 days .

“ This is the first human study to demonstrate a therapeutic effect of DUS-guided cavitation of intravenously administered , commercially available ultrasound contrast agents during acute STEMI ,” the authors , led by Wilson Mathias Jr ., MD , write . “ Early epicardial recanalization rates were significantly higher with the intermittent brief application of HMI impulses to the microcirculation through the apical windows . More importantly , these beneficial effects were evident at

the microvascular level , with improved capillary flow already observed immediately following PCI . The improvement in microvascular perfusion was even more demonstrable at 1-month followup . Because microvascular perfusion frequently remains abnormal following PCI alone in acute STEMI , adding emergency DUS before and after PCI may be a vital supplement that will prevent MVO and its complications .”

Mathias and colleagues add that another purpose of the study was to demonstrate the safety of DUS in this setting , analyzing whether potential harm would occur using DUS-induced cavitation impulses in the early setting of an acute STEMI . They did not observe any clinically relevant differences of any measured hemodynamic parameter . They also wanted to determine whether the addition of an emergencyresponse ultrasound team applying the impulses would interfere with standard of care , best assessed by door-to-dilation time . No differences were observed when compared to a reference group that had no ultrasound interventions at the time of presentation .

“ This is particularly encouraging in that a larger commercial system was used for this study , which could be improved further with more portable systems allowing better access to patients even in ambulances ,” they write .

“ By acutely improving microvascular flow in acute STEMI , DUS also may play a critical supplemental role in preventing the remodeling that leads to further reductions in ejection fraction and increased risk for arrhythmic and heart failure complications ,” the authors conclude . “ Our initial study was too small to examine these differences , but larger trials are warranted to study whether this improvement in microvascular outcome with DUS translates into reduced morbidity and mortality at longer-term follow-up .” In an accompanying editorial comment , Steven B . Feinstein , MD , writes : “ Despite the study limitations , the authors are to be commended for their unique approach to a common and potentially life-threatening problem — salvaging myocardial tissue during an acute infarction . Only time will tell whether this approach proves to be reproducible and generalizable , but the initial results are certainly promising .” ■

Mathias W , Jr ., Tsutsui JM , Tavares BG , et al . J Am Coll Cardiol . 2016 ; 67 ( 21 ): 2506-15 .