Continuous Quality Improvement of Door-to-Balloon Time at a PCI-Capable Hospital
- Volume 19 - Issue 7 - July 2011
- Posted on: 7/5/11
- 0 Comments
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A patient’s treatment and survival of an ST-elevation myocardial infarction (STEMI) is dependent upon the healthcare team’s proficiency in emergent delivery of percutaneous coronary intervention (PCI). Early reperfusion therapy is optimal for salvaging cardiac muscle and improves survival of the patient.1 Door-to-balloon time is a measurement monitored by hospitals in the treatment of a STEMI. The time begins at the patient’s presentation to the emergency room and ends when the compromised vessel is reperfused via coronary intervention. Improved door-to-balloon time is a measure of quality that requires the teamwork of several disciplines. Continuous quality improvement ensures the growth and consistent evolution of a process that works, and is refined and redefined as the standard of care. Herein, we focus on quality improvement procedures initiated at a medical center to decrease door-to-balloon times.
According to the American Heart Association, each year an estimated 785,000 Americans will have a new myocardial infarction (MI), and an estimated 470,000 will have a recurrent MI. Every 25 seconds an American will have a coronary event, and approximately every minute someone will die of one. Coronary artery disease is the leading cause of death for men and women in the United States.2
Many people don’t recognize the warning signs of an MI and delay prompt treatment. According to one study by the CDC conducted in 20053, only 31% of the respondents in the survey knew the five major signs of a heart attack, which include: pain in the neck, jaw, or back; feeling weak or lightheaded; chest pain or discomfort; pain in the arms or shoulders; and shortness of breath.3 In the same study, 86% of the respondents stated they would call 9-1-1 if they thought someone was having a heart attack or stroke. Timely access to emergency care is critical to surviving a heart attack. Half of all cardiac deaths occur within the first hour of symptoms.3 Because early recognition of signs of an MI are critical, the American Heart Association and the National Heart, Lung, and Blood Institute launched the “Act in Time” campaign in 1991 to increase the public’s awareness of heart attack warning signs and symptoms, along with the importance of immediately calling 9-1-1 to strengthen the chain of survival, including advanced life support.3
MIs can occur at any age, but the predisposition to atherosclerosis increases in the presence of hypertension, diabetes, cigarette smoking, and hypercholesterolemia, as well as certain genetic variants.4 The microvascular chain of events can unfold into a cardiac emergency. Typically, there is a sudden disruption in the structure of the arterial plaque that may have been building for a period of time. This disruption may be an intra-lumen hemorrhage, erosion, rupture, or fissure. The exposed endothelial cells experience platelet activation and adhesion. Vasospasms are stimulated, leading to pathways of coagulation resulting in thrombus. Within minutes, the thrombus can evolve into a complete occlusion of the lumen of the coronary vessel. The immediate chemical consequence of ischemia is the change from aerobic glycolysis to anaerobic glycolysis, leading to inadequately produced, high-energy phosphates. The interference with energy metabolism decreases cardiac contractility and leads to the buildup of noxious breakdown products (i.e., lactic acid). Inadequate muscle contraction can lead to heart failure long before cell death occurs. The symptoms may be evidenced by shortness of breath, rapid heartbeat, or chest pain. In spite of these early changes, cell death is not immediate and may be reversible if treated in time.4
“Time is muscle” is a familiar adage for hospitals promoting their cardiac care, but what does that mean? The groundwork for today’s knowledge of emergency cardiac revascularization can be credited to Dr. Eugene Braunwald, an Austrian cardiologist. Through his experimentation with MIs in dogs, Dr. Braunwald realized that an MI could be altered as it is progressing. This was revolutionary at the time and led to current treatment, which is based on the knowledge that aggressive intervention before, during, and after an MI can decrease myocardial damage and save lives. By the 1970’s, Dr. Braunwald’s team proved that injecting thrombolytic agents into blocked arteries could salvage the threatened myocardial tissue by restoring the supply of oxygen to the tissue.5 How much “time” does a patient have before irreversible damage occurs? Fifteen minutes to three hours have been documented in experimental models. Reperfusion therapy can save lives up to 12 hours after onset of symptoms, but this is relative to the extent of the ischemia, the intermittence of the ischemia, or the no-reflow to myocardial tissue post PCI.6 We do know that the best chances of survival are directly related to the time it takes for reperfusion and restoration of oxygen to vital tissue.
A “STEMI” is an ST-elevation myocardial infarction, but what does that look like clinically? The first sign of a possible STEMI is evidenced in patient presentation. Most people believe that the patient typically arrives to the ER with the classic complaints of chest pain, shortness of breath, diaphoresis, and an unexplainable feeling of “doom.” This may be the case, but often the patient may paint a slightly different picture. The patient may “just not feel right,” and the history and physical become central to the diagnosis. The patient may complain of having vague chest pain that was relieved at rest. They may feel a bit fatigued, and now the pain is more visceral and deep, with radiation to the jaw, arm, or back. They may have felt nauseated with indigestion and acquired relief from antacids, but remain apprehensive and restless. Approximately 25% of MIs are “silent,” with atypical or less-prominent symptoms, especially in diabetics, women, and the elderly. Their skin may be cool or pale and diaphoretic. They may be hypertensive initially, with pain, but progress to hypotension due to poor perfusion. Heart sounds may seem distant, with a 4th heart sound often ascultated.7
The second clue to a STEMI is the electrocardiogram (EKG) tracing. An EKG should be ordered as soon as a STEMI is suspected and reviewed immediately. If the initial tracing is normal, it should be repeated, because ST segments can be dynamic. ST segment depression can indicate myocardial ischemia. An elevation of the ST segment that is ≥ 1 mm in two contiguous limb leads indicates current injury. Elevation in leads II, III, and aVF indicate an inferior MI (Figure 1), while ST elevation in leads I, aVL, V5 and V6 indicate anterolateral infarct (Figure 2).8
The third biomarker of a STEMI is an elevated troponin level, specifically, the troponin I and troponin T levels. These improved biomarkers are contractile proteins not normally found in the blood, and elevated serum levels indicate myocardial necrosis. The troponin levels are detectable in serum 3-6 hours following an MI, and can remain elevated up to two weeks, unlike the rapid decrease of CK-MB levels previously monitored.7
Need for Protocols
The diagnosis of a STEMI and its resulting treatment takes the teamwork of several medical disciplines working in concert to efficiently prepare a patient for a PCI. With door-to-balloon time as an important indication of quality, there must be a “best practice” procedure carried out with each patient. STEMI protocols ensure that involved personnel understand what needs to be done and when to do it. Team members from EMS, laboratory, the ER physician, the cardiologist, radiology, cardiopulmonary, cath lab, and ER nurses are the minimum personnel working together for the PCI. Protocols ensure standards of care for all STEMI patients, regardless of who is working that day.
Door-to-Balloon (D2B) Alliance
In 2006, the American College of Cardiology (ACC) realized there was a need to reduce door-to-balloon time for STEMI patients. At that time, only 40% of PCI-capable hospitals were consistently achieving PCI in ≤ 90 minutes. The D2B Alliance was formed with a goal of having PCI-participating hospitals achieve door-to-balloon times of ≤ 90 minutes for at least 75% of the STEMI cases. Strategies included:
- ER physician activates the cath lab
- One call activates the cath lab
- The cath lab team is ready in 20-30 minutes
- Prompt data feedback
- Senior management commitment
- Team-based approach
The American Heart Association and the National Heart Lung and Blood Institute partnered with the ACC to strengthen this effort. The Alliance consists of a community of hospitals and physicians who can educate and support each other in achieving their goals of improved outcomes in this critical area.9 By sharing the protocols and procedures that have worked at each facility, the D2B Alliance helps stimulate other facilities to implement standards that will improve their own door-to-balloon times.
Initial STEMI Protocols
In 2008, the cath lab team at Ochsner Medical Center Baton Rouge (OCMBR) focused their efforts on improving door-to-balloon times to become competitive in cardiac care and remain in compliance with the national standard of door-to-balloon time of ≤ 90 minutes. A letter was sent out by the cath lab supervisor to the system asking for the assistance and support of management and department team members. The letter concluded with a system belief: “No institution can have an excellent reputation for cardiac care without an outstanding STEMI treatment program.” The standards were set. The initial STEMI protocols consisted of standing orders for the ER, a STEMI box housed in the ER that provided the needed supplies and paperwork, and a paging system that began with a call to the cardiologist and continued with consecutively paging each individual cath lab team member. There were no “assigned” duties for ER personnel.
We soon found that this flow of events wasted time and led to confusion and duplication. Consistent stats for door-to-balloon times were not being documented. The need for improvement led to formation of a quality improvement team that consisted of the chief of cardiology, cath lab coordinator, ER nurses, cath lab nurses, hospital QI staff, and telemetry nurses.