Cook spaghetti according to package directions. Meanwhile, in a small bowl, combine the cornstarch, water and broth until smooth; set aside.
In a large skillet, saute garlic and cayenne in oil until garlic is tender. Stir broth mixture and gradually add to the pan. Bring to a boil; cook and stir until thickened, about 2 minutes.
Reduce heat; add the shrimp, lemon juice, zest and parsley. Cook until heated through, 2-4 minutes. Drain spaghetti. Transfer to a large bowl. Add shrimp mixture; toss to coat.
Shrimp is naturally high in cholesterol, but that doesn’t mean it’s off the menu if you’re following a heart-healthy diet. The cholesterol in shrimp is different than the blood cholesterol that you’re trying to manage. Cut back on saturated and trans fats to keep blood cholesterol in check.