Percutaneous Coronary Intervention in Elderly Patients: Part 2
Although several registries suggest that elderly patients who present with cardiogenic shock have a significant improvement in survival with PCI, neither the SHOCK trial nor the Northern New England Shock Study showed much benefit, and may have shown worse outcomes. These studies demonstrated 34% and 12% absolute differences, respectively in early mortality between elderly patients and younger patients with shock treated with PCI.
Elderly patients with cardiogenic shock was one subject of the very complex SHOCK trial and registry. The SHOCK trial randomized 302 patients in cardiogenic shock to early revascularization therapy or to initial medical stabilization. There was significantly lower 6-month mortality in patients randomized to revascularization (PCI or surgical) than those treated medically, but this benefit was observed only in patients < 75 years of age. Patients aged > 75 years did not appear to benefit from a routine strategy of early revascularization. The 30-day survival of patients greater than or equal to 75 years was worse (20.8% vs. 34.4%) in those treated with emergency revascularization. Hochman did not believe these data were definitive, and suggested that baseline differences could have been the determining factor. The principal investigator of SHOCK identified the fact that there were only 56 patients 75 years of age or older enrolled in the SHOCK trial, and hence, a definitive conclusion in this subgroup was not possible. Additionally, the mortality rate for patients > 75 years of age who received initial medical stabilization was similar to younger patients, and was therefore unexpectedly low (53.1%), further qualifying the conclusion. Inequalities in baseline characteristics of the 56 elderly patients assigned to the emergency revascularization group compared to the medical therapy group may also have contributed to an apparent lack of treatment effect.
Conversely, the SHOCK Registry, based on 277 elderly shock patients, did show a marked survival benefit favoring PCI in the elderly. Elderly patients clinically selected for emergency revascularization demonstrated improved survival when treated with emergent PCI. Interestingly, the mean age of randomized patients was lower than registry patients (65.8 vs. 68.5 years; p < 0.001). Again, this suggests an unintentional indirect bias against including higher-risk elderly patients in randomized trials and could well have substantially affected the conclusions of the SHOCK trial.
Other registries have also reported a significant benefit for those elderly who were selected on the basis of physician judgment. In these registries, between 16% and 33% of elderly patients with shock were selected for emergency PCI. The Northern New England Cardiovascular Registry evaluated the results in cardiogenic shock patients over a 10-year experience in their prospective registry in Northern New England. The clinical characteristics and in hospital mortality for elderly patients > 75 years of age were compared to those < 75 years of age. Twenty four percent of a total of 310 patients treated with PCI for cardiogenic shock were greater than or equal to 75 years of age. The mortality rate for elderly shock patients undergoing PCI was 46%, which was significantly less than previously reported in randomized trials. In this registry, there was a 12% absolute difference in total mortality between the elderly and the non-elderly, who had a mortality rate of 34%. The results suggested that the "young elderly", nondiabetic patient with collaterals to infarct-related artery comprised a relatively low-risk group. This highly selected patient group comprised of less acutely ill patients underwent coronary intervention with a lower mortality rate than other series of cardiogenic shock patients, supporting the view that optimal case selection can be appropriately defined.
Several other studies strongly suggest that some elderly shock patients may benefit significantly from PCI. Short- and long-term mortality rates were compared between younger and older patients (greater than or equal to 65 years) in an observational study of 1,263 patients with AMI, of whom 73 (6%) developed cardiogenic shock. In patients without shock, the adjusted relative risk for long-term mortality was 4.4 in older versus younger patients (p < 0.001), while in patients with shock, the adjusted relative risk was 1.8 (p = 0.051). This finding suggests that certain elderly shock patients are highly salvageable. Among the elderly cardiogenic shock patients, estimated 1-year and 5-year survival rates were 38% and 24%. In an observational study of 61 patients greater than or equal to 75 years (mean age 79.5 ± 3 years) treated with primary PCI for AMI with cardiogenic shock, 56% of patients survived to hospital discharge, and the 30-day mortality was 47%. Of the survivors, 75% were alive at 1 year. In 55 octogenarians (mean age 84 ± 3 years) undergoing primary PCI for AMI, 30-day mortality was 4% in patients without cardiogenic shock and 70% in those with shock. The overall 1-year survival rate was 77%. Prasad prospectively evaluated whether physician judgment could be used to determine accurately which elderly shock patients would benefit from emergency PCI. These Mayo Clinic data confirmed that elderly patients selected by their physicians for PCI had better survival than those treated conservatively.
Although several registries suggest that elderly patients who present with cardiogenic shock have a significant improvement in survival with PCI, neither the SHOCK trial nor the Northern New England Shock Study showed much benefit, and may have shown worse outcomes. These studies demonstrated 34% and 12% absolute differences, respectively in early mortality between elderly patients and younger patients with shock treated with PCI.
Elderly patients with cardiogenic shock was one subject of the very complex SHOCK trial and registry. The SHOCK trial randomized 302 patients in cardiogenic shock to early revascularization therapy or to initial medical stabilization. There was significantly lower 6-month mortality in patients randomized to revascularization (PCI or surgical) than those treated medically, but this benefit was observed only in patients < 75 years of age. Patients aged > 75 years did not appear to benefit from a routine strategy of early revascularization. The 30-day survival of patients greater than or equal to 75 years was worse (20.8% vs. 34.4%) in those treated with emergency revascularization. Hochman did not believe these data were definitive, and suggested that baseline differences could have been the determining factor. The principal investigator of SHOCK identified the fact that there were only 56 patients 75 years of age or older enrolled in the SHOCK trial, and hence, a definitive conclusion in this subgroup was not possible. Additionally, the mortality rate for patients > 75 years of age who received initial medical stabilization was similar to younger patients, and was therefore unexpectedly low (53.1%), further qualifying the conclusion. Inequalities in baseline characteristics of the 56 elderly patients assigned to the emergency revascularization group compared to the medical therapy group may also have contributed to an apparent lack of treatment effect.
Conversely, the SHOCK Registry, based on 277 elderly shock patients, did show a marked survival benefit favoring PCI in the elderly. Elderly patients clinically selected for emergency revascularization demonstrated improved survival when treated with emergent PCI. Interestingly, the mean age of randomized patients was lower than registry patients (65.8 vs. 68.5 years; p < 0.001). Again, this suggests an unintentional indirect bias against including higher-risk elderly patients in randomized trials and could well have substantially affected the conclusions of the SHOCK trial.
Other registries have also reported a significant benefit for those elderly who were selected on the basis of physician judgment. In these registries, between 16% and 33% of elderly patients with shock were selected for emergency PCI. The Northern New England Cardiovascular Registry evaluated the results in cardiogenic shock patients over a 10-year experience in their prospective registry in Northern New England. The clinical characteristics and in hospital mortality for elderly patients > 75 years of age were compared to those < 75 years of age. Twenty four percent of a total of 310 patients treated with PCI for cardiogenic shock were greater than or equal to 75 years of age. The mortality rate for elderly shock patients undergoing PCI was 46%, which was significantly less than previously reported in randomized trials. In this registry, there was a 12% absolute difference in total mortality between the elderly and the non-elderly, who had a mortality rate of 34%. The results suggested that the "young elderly", nondiabetic patient with collaterals to infarct-related artery comprised a relatively low-risk group. This highly selected patient group comprised of less acutely ill patients underwent coronary intervention with a lower mortality rate than other series of cardiogenic shock patients, supporting the view that optimal case selection can be appropriately defined.
Several other studies strongly suggest that some elderly shock patients may benefit significantly from PCI. Short- and long-term mortality rates were compared between younger and older patients (greater than or equal to 65 years) in an observational study of 1,263 patients with AMI, of whom 73 (6%) developed cardiogenic shock. In patients without shock, the adjusted relative risk for long-term mortality was 4.4 in older versus younger patients (p < 0.001), while in patients with shock, the adjusted relative risk was 1.8 (p = 0.051). This finding suggests that certain elderly shock patients are highly salvageable. Among the elderly cardiogenic shock patients, estimated 1-year and 5-year survival rates were 38% and 24%. In an observational study of 61 patients greater than or equal to 75 years (mean age 79.5 ± 3 years) treated with primary PCI for AMI with cardiogenic shock, 56% of patients survived to hospital discharge, and the 30-day mortality was 47%. Of the survivors, 75% were alive at 1 year. In 55 octogenarians (mean age 84 ± 3 years) undergoing primary PCI for AMI, 30-day mortality was 4% in patients without cardiogenic shock and 70% in those with shock. The overall 1-year survival rate was 77%. Prasad prospectively evaluated whether physician judgment could be used to determine accurately which elderly shock patients would benefit from emergency PCI. These Mayo Clinic data confirmed that elderly patients selected by their physicians for PCI had better survival than those treated conservatively.
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