August 20th, 2010

Door to Balloon (D2B) Time: The Wrong Performance Measure?

The authors of a recently published study evaluated the association between system delay (i.e., time from the patient’s first contact with the health care system to initiation of reperfusion) and outcome in STEMI patients transported by EMS and treated with primary PCI.  Some patients were triaged directly to a PCI center, whereas others were transported to their local hospitals before transfer to a PCI center.

Compared with patients triaged directly to a PCI center, those transferred to a PCI center had a shorter D2B time (29 vs. 39 min, P<0.001) but a longer total health system delay (240 min vs. 172 min; P<0.001). Importantly, this delay substantially influenced long-term (3.4-year) mortality, which was 15% of those with a treatment delay of 0-60 minutes, 23% with a delay of 61-120 minutes, 28% with a delay of 121-180 minutes, and 31% with a delay of 181-360 minutes (P<0.001).

Apparently, transfer to another facility for primary PCI might not constitute optimal care of the AMI patient. Given regional variations in treatment delay, how do you decide how to treat these patients?

12 Responses to “Door to Balloon (D2B) Time: The Wrong Performance Measure?”

  1. I am curious how many hospitals track these times. Surely the decision to transfer should take into consideration the time involved. CMS is now collecting the time it takes for hospitals to transfer paitents out for primary PCI. The public reporting of that data could help focus attention on this issue.

  2. Having been one of the first cardiologists to invasively treat acute myocardial infarction, see NEJM December 6, 1984, I can say that the pertinant time frame is from the onset of SYMPTOMS to the opening of the occlusion. This is not the same as door to balloon time. Opening of the vessel can be accomplished by non invasive pharmocological means as well as by mechanical interventions. Each has its place.

    Competing interests pertaining specifically to this post, comment, or both:
    None, I am retired.

  3. Dr Schneider, you are of course right that the most important time frame starts with the onset of symptoms, but, unfortunately, until the patient enters the system there is so far little or nothing that has been found to speed their entrance into the system. In terms of establishing performance measures, clearly one should only consider measures that the health care system can influence.

  4. Dr. Huston, The health care system can influence the time to treatment once the patient enters it. As I carefully stated, this treatment “can be accomplished by non invasive pharmolcologic means”. This was meant to relate to intravenous thrombolytic therapy. When I was attending conferences, after I retired, at the Univesity of Pittsburgh division of cardiology, one of the top 20 rated cardiology divisions in the country, a few years back I was informed that the fellows were not even being taught how to use IV thrombolytics. When I brought up the necessity of this training I was repeatedly told that this form of treatment of AMI would NOT be taught.

    My sense of this, unfortunately, was that the fellows were being taught to rely on referral to the tertiary care facility, ie UPMC, once they went into the community to practice, in order to maintain the volume of procedures in the cath lab. This may not have been the case, but I couldn’t think of any other reason why the fellows would deliberately not be taught about the proper use of IV thrombolytics to treat AMI.

    I read a study recently that indicated that the administration of IV thrombolytic therapy is NOT a contraindication of immediate subsequent PCI, as it was once thought to be. Studies have shown that with the proper communication from experienced cardiologists to first responders and ER phyicians IV thrombolytic Rx can be administered, in some cases, hours prior to the balloon entering the occluded vessel. The 90 minute reperfusion rate with IV thrombolytic Rx is more than 50%, and probably as high as 80% in some studies.

    The proper use of IV thrombolytic Rx requires training, education, and committment. It can have serious complications, including fatal cerebral hemmorhage and other serious bleeding, if used in the wrong patient, but when used properly it will definitely improve overall outcomes both in terms of morbidity and mortality.

    Competing interests pertaining specifically to this post, comment, or both:

  5. In fact, in many centers, academic and otherwise, thrombolytic therapy is seldom, if ever, given. As a result, the fellows and residents have limited (or no) experience with it.

  6. That is a really interesting point – are we training fellows in academic centers who have no idea how to use lytics?

  7. Certainly that is true in Dallas and San Antonio.

  8. Yale, too. Probably most of the Fellows graduating in the country have never administered lytics. Or been involved in the decision.

  9. Agree, and that’s also the case for the vast majority of fellows graduating from programs in Baltimore and Boston.

  10. Similar to our experience here in St. Louis. Moreover the D2B goals have taken the fellow almost entirely out of the decision making process for STEMIs in the ED as our ED MDs communicate directly with our interventional attendings. That being said we still rely on our fellows to evaluate these patients as the cath lab is coming in.

    Although we preferentially use primary PCI in the vast majority of our STEMI patients, it is important that fellows are aware of the indication/contraindications for lytics. I guess that is where the eduaction part comes in. Of course there is no substitute for experience but is there anyone who would advocate lytics when PCI is available 24/7?.

  11. That’s the entire point. What is the actual definition of “PCI is available 24/7”. Available how fast? Still, I believe, the majority of infarct patients still present to community hospitals where PCI is not available and from which patients must be transferred to another facility for the procedure. Board Certified Cardiologists and Emergency Room physicians are IMMEDIATELY available in many hospitals that do not have PCI facilities. They are certainly available to the patient prior to transfer. IV thrombolytics SHOULD and MUST be delivered to appropriate patients by those physicians when it is anticipated that a balloon will not be able to enter the infarct related coronary artery in less than 90-120 minutes. This delay could also be due to travel distances or traffic conditions or weather conditions that make travel very slow or impossible by either ground or air transportation. The OPTION of IV throbolytic therapy to treat AMI, must always be available and considered by the intitial contact physician. In fact, given my extensive experience with malpractice issues, I think that not giving IV thrombolytics to such a patient in a timely manner could even be considered a basis for a malpractice suit in some circumstances.

    In addition, some studies, I believe one from Israel years ago, indicated that with electronic communication of initial ECG to an experienced clinician, and good verbal communication, ambulance personel could deliver thromblytic therapy safely in the ambulance on the way to a community hospital not equipped with PCI facilities prior to the transfer to a tertiary car hospital with such facilities.

    It seems to me that academic institions that do not train their fellows in the proper use of IV Thrombolytic therapy for AMI are seriously negligant. But my impression, having worked in both academic and community hospitals, is that academic cardiology attendings who do research and publish papers and care for patients in large hospitals equipped to do 24/7 PCI have absolutely no idea themselves how to properly use thrombolytics and that’s why they don’t teach and don’t want to teach its use. They don’t know it themselves.

    Academic centers are under financial pressures to maintain as high a volume in the cath lab as possible, so they have a financial disincentive to teach their fellows to administer thrombolytic therapy in the outlying community rather than routine immediate transfer to the academic center. But now that we know that acute PCI is not contraindicated in AMI patients who have already received IV thrombolytics this should no longer be a medical consideration. Of course, in additon, some patients who receive IV thrombolytics will stabilize completely in less than an hour due to rapid reperfusion, and in those cases the interventional cardiologist in the tertiary care facility might well make the clinical decision to defer immediate emergency PCI.

    In some cases, patients treated with IV thrombolytics for a totally occluded IRA may actully have a residual stenosis of less than 50% after several days. This could be due to resorption of the acute hemmorhage into the plaque or possible rapid healing of the plaque rupture. In such a case, even elective PCI might not be indicated. In addition, a post infarct angiogram in a patient only treated with IV meds might indicate triple vessel disease requiring CABG. In both of these circumstances the PCI would not be done and the volume of PCI’s performed for that facility would go down. This is directly opposed to the financial and academic interests of the Division of Cardiology in that institution.

    Do you think that this might effect the reasoning behind why fellows are not taught to properly use IV thrombolytics to treat AMI in the community? I do.

    Competing interests pertaining specifically to this post, comment, or both:
    None, I am retired.

  12. The use of IV thrombolytics is an art and can be beneficial in institutions with no PCI facilities or there is significant PCI related delay. Some patients who underwent unsuccessful PPCI for IRA with heavy thrombus burden, occlusion or complex lesion without immediate recourse for CABG may actually benefit from IV thrombolytics to improve the TIMI score. I have seen these patients languishing in the CCU receiving neither invasive or pharmacological thrombolysis while awaiting for surgery.

    Competing interests pertaining specifically to this post, comment, or both: