Managing Restenosis with Home Rhythm monitoring post PCI

Percutaneous coronary intervention or PCI is a non-surgical method used to open narrowed or blocked arteries. It is also called percutaneous transluminal coronary angioplasty (PTCA). Types of percutaneous coronary intervention include: balloon angioplasty and drug-coated stents. Complications are rare and typically involve a blood clot if the artery tears at the balloon site, failure of PCI to work and hematoma at the catheter entry site. PCI can be used to relieve angina, avoid heart attacks, lessen congestive heart failure, and allows some patients to avoid surgical treatment (coronary artery bypass graft or CABG) that involves extensive surgery and often long rehabilitation time. As PCI technique has advanced from balloon, to balloon plus stent, to balloon plus drug-eluting stent, the long-term results have improved so recurrent narrowing or blockage occurs in less than 10% of patients. If there is no evidence of recurrence of narrowing or blockage after about12 months, the majority of stented coronary arteries remain open in the stented area for many years. Patients who fail to take their prescribed anti-platelet medication and continue a lifestyle that promotes coronary artery cholesterol accumulation and arterial narrowing are more likely to have either stent failure or have additional arterial areas develop narrowing or blockage.

Angioplasty is often used interventional technique for removing blockage of an artery since mid1980’s. However, at least 50% of people after the procedure experienced symptoms of blockage caused due to restenosis within few months or years. Restenosis is the recurrence of stenosis, a narrowing of a blood vessel, leading to restricted blood flow. Restenosis usually pertains to an artery or other large blood vessel that has become narrowed, received treatment to clear the blockage and subsequently become renarrowed. This is usually restenosis of an artery, or other blood vessel, or possibly a vessel within an organ. . The most important risk factors are Diabetes mellitus, Hypertension, Smoking, delayed Healing process and Hypersensitivity to the stent product. Mechanical causes may also cause restenosis. This may be under expansion of stents, improper placement of the stent to the vessel wall, impairment of drug eluting property of the stent faced due to difficulty in proper implantation of the stent. Restenosis occurs when the treated vessel becomes blocked again. It usually occurs within 6 months after the initial procedure. Compared with balloon angioplasty alone, where the chance of restenosis is 40%, stents reduce the chance of restenosis to 25%.6,7. Therefore, the majority of patients having angioplasty today are treated with stents.

Restenosis is a common adverse event of endovascular procedures. Procedures frequently used to treat the vascular damage from atherosclerosis and related narrowing and renarrowing (restenosis) of blood vessels include vascular surgery, cardiac surgery, and angioplasty. When a restenosis occurs with stent, this is called in-stent restenosis or ISR. If it occurs following balloon angioplasty, this is called post-angioplasty restenosis or PARS. The diagnostic threshold for restenosis in both ISR or PARS is ≥50% stenosis. Rates of restenosis differ between devices (e.g., stent-grafts, balloon angioplasty, etc.) and location of procedure (i.e., centrally-located in the heart such as the coronary artery, or in peripheral vessels such as the popliteal artery in the leg, the pudendal artery in the pelvis, or the carotid artery in the neck). In cardiac procedures, balloon angioplasty has been associated with a high incidence of restenosis, with rates ranging from 25% to 50%, and the majority of these patients need further angioplasty within 6 months.

A 2010 study in India comparing coronary drug-eluting stents (DES) with coronary bare-metal stents (BMS) reported that restenosis developed in 23.1% of DES patients vs 48.8% in BMS patients, and female sex was found to be a statistically significant risk factor for developing restenosis.

Different researches have shown that placing multiple stents can double the risk of restenosis, which is due to a greater length of the primary lesion and a larger surface that is covered by stent material. This is the reason why the success of applied interventional method is determined not only by its efficiency and reliability in recovering the lumen, but also by reducing the risk of restenosis. Predictors of restenosis are small vessel size, increased stented length, complex lesion morphology, diabetes mellitus, and prior bypass surgery.

The pathophysiologic mechanism of restenosis is unknown yet, but gathered evidence strongly suggests that intimal hyperplasia is the major mechanism. Based on existing understanding of intimal hyperplasia, one concept may be that there are at least two major local biological determinants influencing the process, lesion characteristics and regional flow dynamics. Lesion characteristics include the plaque structure and the quantity of smooth muscle .Angiographic restenosis is commonly adjudicated as a binary event defined as a re-narrowing of 50% of the vessel diameter as determined by coronary angiography. In one recent study, only 30% of restenosis could be predicted from clinical, procedural, and angiographic variables.

The common manifestation of clinically relevant restenosis is exercise-induced angina, followed by unstable angina (25%) and acute myocardial infarction (5–10%). In patients who present with recurrent chest pain, angiographic restenosis at follow-up angiography is predicted by following factors. Patients who present 1-6 months after angioplasty with typical anginal symptoms have a high likelihood of having angiographic restenosis. On the other hand, patients who present more than 6 months after PCI with recurrent chest pain are more likely to have new, significant coronary lesions to account for their symptoms. Angina is chest pain or discomfort caused when your heart muscle doesn't get enough oxygen-rich blood. It may feel like pressure or squeezing in your chest. The discomfort also can occur in your shoulders, arms, neck, jaw, or back. Angina pain may even feel like indigestion. Angina is of following types: Angina Pectoris, Unstable Angina, Variant (Prinzmetal) Angina and Microvascular Angina.

A correct diagnosis is important because it can predict the likelihood of having a heart attack. ECG, Stress test, Chest X-ray, Coronary angiography and Blood tests are the tools for diagnosis.

Coronary heart disease (CHD) remains the leading cause of death in the United States, accounting for 26.6% of all deaths in 2005, with an age-adjusted male to female mortality ratio of 1.5. Although the CHD mortality rate has gradually declined since its peak in the 1960s, morbidity from CHD has shown conflicting trends, with increasing rates of revascularization and an increasing occurrence of angina pectoris, now estimated at 9.1 million (4.6 million women [3.9%]; 4.4 million men [4.4%]). In stark contrast to CHD mortality rates, age-adjusted prevalence rates for angina in the United States are higher among women than men. Anginal symptoms tend to persist despite medical therapy and revascularization, lead to substantial functional disability, and be associated with high healthcare costs even in the absence of obstructive coronary artery disease (CAD).

Acute myocardial infarction is a major cause of death and morbidity in the United States and the symptom onset to arrival at hospital times remain at 2.5 to 3 hours 28-30. This delay in treatment results in potentially irreversible myocardial infarction and lethal arrhythmia that may have been avoided if diagnosed earlier. Early diagnosis is the key factor. ECG provides monitoring of heart rhythms.

In a study of a group of 2000 volunteers in a New England community, the relative merits of the 12-lead and a simplified lead I electrocardiogram in the detection of heart disease were compared. It is concluded that if the ECG is to be used for screening, the speed and ease of the technic and the slight loss of efficiency in the use of lead I alone compared with the 12-lead electrocardiogram would appear to make lead I the method of choice for the screening line.

Continuous care is required post PCI to reduce the prevalence of restenosis. The utility of home-based programs for cardiac rehab hold the promise of improved compliance rates but still requires monitoring by a nurse or trained technician. Home-based cardiac monitoring in conjunction with wireless ECG, blood pressure and heart rate monitoring may provide a means of improving compliance while maximizing safety and better individualizing management strategies and education arising in real-world activities. A study conducted in Korea randomized 50 patients to conventional care vs. home-based cardiac rehab for 12 weeks while monitoring ECG, the home-based cardiac rehab group showed significantly improved ejection fraction and a reduced number of regional wall motion abnormalities. This type of home-based training can be further applied to other chronic conditions such as peripheral arterial disease and CHF.

Longer monitoring is often necessary to detect Afib, because the disordered heart rhythm may last just a few minutes and occur only occasionally. So a brief ECG done may not pick up all the waves. A typical ECG uses 12 electrodes placed on the chest, arms, and legs to record the heart's electrical activity. But a simpler version, known as a single-lead ECG is sufficient to detect an irregular pulse and rhythm, which is the precursor for Afib. 30-second recordings can be shared with cardiologist to help early diagnosis and treatment. People diagnosed with Afib typically take anti-clotting drugs to lower their risk of stroke.

Cardiac care has undergone a significant change with advancement in technology. A main finding has been that patients undergoing PCI find it challenging to move across the boundaries and each type of continuity – informational, management and relational – which has an important impact on a patient’s experience of how care is connected. In order to ensure that health care providers provide quality care to patients who have PCI procedures, knowledge and skill must keep pace with technology and evidence-based practices. Single-lead ECG systems not only work, but they work remarkably well for conducting both 12-lead and exercise ECGs. Using interpretations from medical-grade single-lead ECG can contribute towards earlier detection and treatment of potentially fatal heart rhythm disorders, and, the potential to save lives. Having the control to take an ECG at any time also means people can feel closer to their heart health which will also help take away some of their anxiety. The huge benefit of this technology is that it saves appointments because diagnosis can be made in a single step, which means less time and money wasted on appointments and follow ups for doctors and the patient. The evolution of these wireless cardiac monitoring devices will mark a new era in medicine and a transition from population level health care to individualized medicine where suitable patients are equipped with advanced biosensors that, in turn, have their data processed through sophisticated algorithms to predict events before they occur.